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Sample records for aqueous nitric acid

  1. Speciation in aqueous solutions of nitric acid.

    PubMed

    Hlushak, S; Simonin, J P; De Sio, S; Bernard, O; Ruas, A; Pochon, P; Jan, S; Moisy, P

    2013-02-28

    In this study, speciation in aqueous solutions of nitric acid at 25 °C was assessed in two independent ways. First, Raman experiments were carried out and interpreted in terms of free nitrate ions, ion pairs and neutral HNO(3) molecules. In parallel, a model was developed to account for the formation of these two kinds of pairs. It was based on an extension of the binding mean spherical approximation (BiMSA), or associative MSA (AMSA), in which the size and the charge of the ions in the chemical pair may differ from those of the free ions. A simultaneous fit of the osmotic coefficient and of the proportion of free ions (obtained from Raman spectroscopy experiments) led to an estimation of the speciation in nitric acid solutions. The result obtained using this procedure was compared with the estimation obtained from the Raman experiments. PMID:23258765

  2. RECOVERY OF ACTINIDES FROM AQUEOUS NITRIC ACID SOLUTIONS

    DOEpatents

    Ader, M.

    1963-11-19

    A process of recovering actinides is presented. Tetravalent actinides are extracted from rare earths in an aqueous nitric acid solution with a ketone and back-extracted from the ketone into an aqueous medium. The aqueous actinide solution thus obtained, prior to concentration by boiling, is sparged with steam to reduce its ketone to a maximum content of 3 grams per liter. (AEC)

  3. Polymerization of Pu(IV) in aqueous nitric acid solutions

    SciTech Connect

    Toth, L.M.; Friedman, H.A.; Osborne, M.M.

    1980-10-01

    The polymerization of Pu(IV) in aqueous nitric acid solutions has been studied spectrophotometrically both to establish the influence of large UO{sub 2}(NO{sub 3}){sub 2} concentrations on the polymerization rates and, more generally, to review the influence of the major parameters on the polymer reaction. Typically, experiments have been performed at 50{sup 0}C and with 0.05 M Pu in nitric acid solutions that vary in acidity from 0.07 to 0.4 M. An induction period usually precedes the polymer growth stage during which time nucleation of primary hydrolysis products occurs. Uranyl nitrate retards the polymerization reaction by approximately 35% in spite of the counteracting influence of the nitrate ions associated with this solute. The rate of polymer formation, expressed as d(percent polymer)/dt, has been shown to depend on the total plutonium concentration in reactions where the Pu(IV) concentration remained constant; and it is therefore suggested that the polymer reaction rate is not first order with respect to the concentration of plutonium as was previously thought. It has been shown further that accurate acid determinations on stock reagents are essential in order to obtain reliable polymerization experiments. Satisfactory procedures for these analyses did not exist, so appropriate modifications to the iodate precipitation methods were developed. The most ideal plutonium reagent material has been shown to be crystalline Pu(IV) nitrate because it can be added directly to acid solutions without the occurrence of unintentional hydrolysis reactions.

  4. Extraction of nitric acid, uranyl nitrate, and bismuth nitrate from aqueous nitric acid solutions with CMPO

    SciTech Connect

    Spencer, B.B.

    1995-08-01

    DOE sponsored development of the transuranium extraction (TRUEX) process for removing actinides from radioactive wastes. The solvent is a mixture of CMPO and TBP. Since the extraction characteristics of CMPO are not as well understood as those of TBP, the extraction of nitric acid, uranyl nitrate, and bismuth nitrate with CMPO (dissolved in n-dodecane) were studied. Results indicate that CMPO extracts nitric acid with a 1:1 stoichiometry; equilibrium constant is 2. 660{plus_minus}0.092 at 25 C, and extraction enthalpy is -5. 46{plus_minus}0.46 kcal/mol. Slope analysis indicates that uranyl nitrate extracts with a mixed equilibria of 1:1 and 2:1 stoichiometries in nearly equal proportion. Equil. constant of the 2: 1 extraction was 1.213 {times} 10{sup 6}{plus_minus}3.56 {times} 10{sup 4} at 25 C; reaction enthalpy was -9.610{plus_minus}0.594 kcal/mol. Nitration complexation constant is 8.412{plus_minus}0.579, with an enthalpy of -10.72{plus_minus}1.87 kcal/mol. Bismuth nitrate also extracts with a mixed equilibria of (perhaps) 1:1 and 2:1 stoichiometries. A 2:1 extraction equilibrium and a nitrate complexation adequately model the data. Kinetics and enthalpies were also measured.

  5. Studies on the adsorption of americium on alumina from aqueous nitric acid-oxalic acid solutions

    SciTech Connect

    Subba Rao, M.; Gaikwad, A.M.; Rao, V.K.; Natarajan, P.R.

    1985-01-01

    This paper reports a study on the adsorption of Am(III) on alumina from oxalic acid-nitric acid solutions. Distribution coefficients for Am(III) on alumina at different oxalic acid-nitric acid concentrations have been determined and optimum conditions for loading and elution of Am from alumina columns have been established. Separation of Am from Pu and the effects of other ions, such as U(VI) and Fe(III), have also been studied. Am and Pu recoveries better than 99.5% were obtained. 3 references, 2 figures, 5 tables.

  6. Simultaneous determination of nitric acid and uranium concentrations in aqueous solution from measurements of electrical conductivity, density, and temperature

    SciTech Connect

    Spencer, B.B.

    1991-01-01

    Nuclear fuel reprocessing plants handle aqueous solutions of nitric acid and uranium in large quantities. Automatic control of process operations requires reliable measurements of these solutes concentration, but this is difficult to directly measure. Physical properties such as solution density and electrical conductivity vary with solute concentration and temperature. Conductivity, density and temperature can be measured accurately with relatively simple and inexpensive devices. These properties can be used to determine solute concentrations will good correlations. This paper provides the appropriate correlations for solutions containing 2 to 6 Molar (M) nitric acid and 0 to 300 g/L uranium metal at temperatures from 25--90{degrees}C. The equations are most accurate below 5 M nitric acid, due to a broad maximum in the conductivity curve at 6 M. 12 refs., 9 figs., 6 tabs.

  7. NITRIC ACID PICKLING PROCESS

    DOEpatents

    Boller, E.R.; Eubank, L.D.

    1958-08-19

    An improved process is described for the treatment of metallic uranium surfaces preparatory to being given hot dip coatings. The process consists in first pickling the uraniunn surInce with aqueous 50% to 70% nitric acid, at 60 to 70 deg C, for about 5 minutes, rinsing the acid solution from the uranium article, promptly drying and then passing it through a molten alkali-metal halide flux consisting of 42% LiCl, 53% KCla and 5% NaCl into a molten metal bath consisting of 85 parts by weight of zinc and 15 parts by weight of aluminum

  8. Spectrophotometric determination of Rare Earth Elements in aqueous nitric acid solutions for process control.

    PubMed

    Rodionova, Oxana Ye; Tikhomirova, Tatyana I; Pomerantsev, Alexey L

    2015-04-15

    Noninvasive analytical control is of special interest for the complicated and hazardous production processes. On-line monitoring provides a unique opportunity to determine critical concentrations rapidly and without serious risks to operating personnel and the environment. Models for quantitative determination of concentrations of Rare Earth Elements in complex mixtures in nitric acid serve for these purposes. Here, the feasibility of simultaneous determination of cerium, praseodymium, and neodymium using the whole UV-vis spectroscopic range, together with chemometric data processing, is studied. The predictability of two chemometric techniques, partial least squares regression and correlation constrained multivariate curve resolution-alternating least squares are compared. Models' performances are analyzed in out-of-control cases. PMID:25818140

  9. Nitric acid recovery from waste solutions

    DOEpatents

    Wilson, A. S.

    1959-04-14

    The recovery of nitric acid from aqueous nitrate solutions containing fission products as impurities is described. It is desirable to subject such solutions to concentration by evaporation since nitric acid is regenerated thereby. A difficulty, however, is that the highly radioactive fission product ruthenium is volatilized together with the nitric acid. It has been found that by adding nitrous acid, ruthenium volatilization is suppressed and reduced to a negligible degree so that the distillate obtained is practically free of ruthenium.

  10. NITRIC ACID RECPVERY FROM WASTE COLUTIONS

    DOEpatents

    Wilson, A.S.

    1959-04-14

    The recovery of nitric acid from aqueous nitrate solutions containing fission products as impurities is described. It is desirable to subject such solutions to concentration by evaporation since nitric acid is regenerated thereby. A difficulty, however, is that the highly radioactive fission product ruthenium is volatilized together with the nitric acid. It has been found that by adding nitrous acids ruthenium volatilization is suppressed and reduced to a negligible degree so that the distillate obtained is practically free of rutheniuim.

  11. Utilization of cation exchange resins for the isolation and separation of transplutonium elements from others in aqueous and non aqueous-alcohol solutions of hydrochloric and nitric acids

    SciTech Connect

    Guseva, L.I.; Tikhomirova, G.S.

    1985-07-01

    The authors study the sorption of several transplutonium and fission elements on cation exchange resins in relation to the acid concentration and content of alcohol in solution. They observe a significant increase in sorption of the TPE on the cation exchanges from nitric acid solutions containing more than 50% of alcohol. On the basis of the experimental results they determine the optimum conditions for the concentration of TPE on cation exchangers with their subsequent separation from certain fission and other elements by means of hydrochloric acid and nitric acid solutions.

  12. Improvement of oxygen-containing functional groups on olive stones activated carbon by ozone and nitric acid for heavy metals removal from aqueous phase.

    PubMed

    Bohli, Thouraya; Ouederni, Abdelmottaleb

    2016-08-01

    Recently, modification of surface structure of activated carbons in order to improve their adsorption performance toward especial pollutants has gained great interest. Oxygen-containing functional groups have been devoted as the main responsible for heavy metal binding on the activated carbon surface; their introduction or enhancement needs specific modification and impregnation methods. In the present work, olive stones activated carbon (COSAC) undergoes surface modifications in gaseous phase using ozone (O3) and in liquid phase using nitric acid (HNO3). The activated carbon samples were characterized using N2 adsorption-desorption isotherm, SEM, pHpzc, FTIR, and Boehm titration. The activated carbon parent (COSAC) has a high surface area of 1194 m(2)/g and shows a predominantly microporous structure. Oxidation treatments with nitric acid and ozone show a decrease in both specific surface area and micropore volumes, whereas these acidic treatments have led to a fixation of high amount of surface oxygen functional groups, thus making the carbon surface more hydrophilic. Activated carbon samples were used as an adsorbent matrix for the removal of Co(II), Ni(II), and Cu(II) heavy metal ions from aqueous solutions. Adsorption isotherms were obtained at 30 °C, and the data are well fitted to the Redlich-Peterson and Langmuir equation. Results show that oxidized COSACs, especially COSAC(HNO3), are capable to remove more Co(II), Cu(II), and Ni(II) from aqueous solution. Nitric acid-oxidized olive stones activated carbon was tested in its ability to remove metal ions from binary systems and results show an important maximum adsorbed amount as compared to single systems. PMID:25794582

  13. Effect of ultrasonic frequency on H2O2 sonochemical formation rate in aqueous nitric acid solutions in the presence of oxygen.

    PubMed

    Dalodière, Elodie; Virot, Matthieu; Moisy, Philippe; Nikitenko, Sergey I

    2016-03-01

    The influence of the ultrasonic frequency (20 kHz, 207 kHz, and 615 kHz) towards the formation kinetics of H2O2 under Ar and Ar/(20 vol.%)O2 atmospheres was evaluated in pure water and aqueous nitric solutions. Results obtained at low frequency ultrasound demonstrate that hydrogen peroxide formation is enhanced under an Ar/O2 gas mixture whatever the sonicated medium. Nevertheless, H2O2 yields are higher in aqueous nitric solutions whatever the nature of the saturating gas. These observations are consistent at high frequency ultrasound under Ar gas notwithstanding higher yields for H2O2. Surprisingly, an inverse tendency is observed for high frequency sonolysis carried out under an Ar/O2 atmosphere: higher yields of H2O2 are measured in pure water. Further studies in the presence of pure Ar revealed a more important decomposition of nitric acid under high frequency ultrasound leading to higher yields of both HNO2 in the liquid phase and NO in the gas phase. In the presence of Ar/O2 mixture, the intrabubble oxidation of NO causes cavitation bubble depletion in O2 leading to the drop of H2O2 yield. On the other hand, it was found that for Ar/(20 vol.%)O2 mixture there is no influence of oxygen on HNO2 yield whatever the ultrasonic frequency; this is most likely explained by two processes: (i) HNO2 formation results from nitrate-ion thermolysis in the liquid reaction zone surrounding the cavitation bubble, and (ii) effective intrabubble oxidation of NOx species by oxygen to nitrate-ion. PMID:26584999

  14. REDUCTION OF ACIDITY OF NITRIC ACID SOLUTIONS BY USE OF FORMALDEHYDE

    DOEpatents

    Healy, T.V.

    1958-05-20

    A continuous method is described of concentrating by evaporation and reducing the nitrate ion content of an aqueous solution of metallic salts containing nitric acid not in excess of 8N. It consists of heating the solution and then passing formaldehyde into the heated solution to bring about decomposition of the nitric acid. The evolved gases containing NO are contacted countercurrently with an aqueous metal salt solution containing nitric acid in excess of 8N so as to bring about decomposition of the nitric acid and lower the normality to at least 8N, whereupon it is passed into the body of heated solution.

  15. 49 CFR 173.158 - Nitric acid.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as... sulfuric acid or hydrochloric acid as impurities, when offered for transportation or transported by rail... 49 Transportation 2 2014-10-01 2014-10-01 false Nitric acid. 173.158 Section...

  16. 49 CFR 173.158 - Nitric acid.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as... sulfuric acid or hydrochloric acid as impurities, when offered for transportation or transported by rail... 49 Transportation 2 2011-10-01 2011-10-01 false Nitric acid. 173.158 Section...

  17. 49 CFR 173.158 - Nitric acid.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as... sulfuric acid or hydrochloric acid as impurities, when offered for transportation or transported by rail... 49 Transportation 2 2010-10-01 2010-10-01 false Nitric acid. 173.158 Section...

  18. 49 CFR 173.158 - Nitric acid.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as... sulfuric acid or hydrochloric acid as impurities, when offered for transportation or transported by rail... 49 Transportation 2 2013-10-01 2013-10-01 false Nitric acid. 173.158 Section...

  19. Nitric acid requirement for treating sludge

    SciTech Connect

    Hsu, C.W.

    1992-09-04

    The hydroxylamine nitrate (HAN) precipitate hydrolysis process produces sufficient oxidant (nitrate) such that the resulting blend of formic acid treated sludge and the aqueous product from hydrolysis (PHA) produces a melter feed of acceptable redox (i.e. Fe+2/Total Fe <0.33). With implementation of Late Washing (to reduce the nitrite content of the tetraphenyborate slurry produced during In-Tank Precipitation to 0.01M or less), HAN is no longer required during hydrolysis. As a result, the nitrate content of the melter feed will be reduced greater than an order-of-magnitude and the resulting melter feed produced will be too reducing. If formic acid treatment of the sludge is retained, it will be necessary to trim the melter feed with an oxidant to attain a proper redox. Rather than trimming the melter feed with an oxidant subsequent to the SRAT cycle in which formic acid is used to acidify the sludge, the Savannah River Technology Center (SRTC) has recommended this be accomplished by conversion to nitric acid addition to the Sludge Receipt and Adjustment Tank (SRAT) in place of formic acid (1). This memorandum specifies the stoichiometric bases for determining the nitric acid requirement for the SRAT.

  20. Corrosion studies in fuel element reprocessing environments containing nitric acid

    SciTech Connect

    Beavers, J A; White, R R; Berry, W E; Griess, J C

    1982-04-01

    Nitric acid is universally used in aqueous fuel element reprocessing plants; however, in the processing scheme being developed by the Consolidated Fuel Reprocessing Program, some of the equipment will be exposed to nitric acid under conditions not previously encountered in fuel element reprocessing plants. A previous report presented corrosion data obtained in hyperazeotropic nitric acid and in concentrated magnesium nitrate solutions used in its preparation. The results presented in this report are concerned with the following: (1) corrosion of titanium in nitric acid; (2) corrosion of nickel-base alloys in a nitric acid-hydrofluoric acid solution; (3) the formation of Cr(VI), which enhances corrosion, in nitric acid solutions; and (4) corrosion of mechanical pipe connectors in nitric acid. The results show that the corrosion rate of titanium increased with the refreshment rate of boiling nitric acid, but the effect diminished rapidly as the temperature decreased. The addition of iodic acid inhibited attack. Also, up to 200 ppM of fluoride in 70% HNO/sub 3/ had no major effect on the corrosion of either titanium or tantalum. In boiling 8 M HNO/sub 3/-0.05 M HF, Inconel 671 was more resistant than Inconel 690, but both alloys experienced end-grain attack. In the case of Inconel 671, heat treatment was very important; annealed and quenched material was much more resistant than furnace-cooled material.The rate of oxidation of Cr(III) to Cr(VI) increased significantly as the nitric acid concentration increased, and certain forms of ruthenium in the solution seemed to accelerate the rate of formation. Mechanical connectors of T-304L stainless steel experienced end-grain attack on the exposed pipe ends, and seal rings of both stainless steel and a titanium alloy (6% Al-4% V) underwent heavy attack in boiling 8 M HNO/sub 3/.

  1. The Oxidation of Hydrazine by Nitric Acid

    SciTech Connect

    Karraker, D.G.

    2001-07-02

    Hydrazine nitrate-nitric acid solutions are used in the ion exchange process for separating Pu-238 and Np-237 and have been found to dissolve plutonium metal in a manner advantageous to SRP metal recovery operations. Laboratory tests on the stability of hydrazine in nitric acid solutions were performed to obtain accurate data, and the results of these tests are reported here. These tests provide sufficient information to specify temperature control for hydrazine-nitric acid solutions in plant processes.

  2. Alternative to Nitric Acid Passivation

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2015-01-01

    The Ground Systems Development and Operations (GSDO) Program at NASA John F. Kennedy Space Center (KSC), Florida, has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described as the launch support and infrastructure modernization program in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of NASA and the GSDO Program, the objective of this project is to qualify citric acid as an environmentally-preferable alternative to nitric acid for passivation of stainless steel alloys. This project is a direct follow-on to United Space Alliance (USA) work at KSC to optimize the parameters for the use of citric acid and verify effectiveness. This project will build off of the USA study to further evaluate citric acids effectiveness and suitability for corrosion protection of a number of stainless steels alloys used by NASA, the Department of Defense (DoD), and the European Space Agency (ESA).

  3. Citric Acid Alternative to Nitric Acid Passivation

    NASA Technical Reports Server (NTRS)

    Lewis, Pattie L. (Compiler)

    2013-01-01

    The Ground Systems Development and Operations GSDO) Program at NASA John F. Kennedy Space Center (KSC) has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described as the launch support and infrastructure modernization program in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of the GSDO Program, the purpose of this project is to demonstratevalidate citric acid as a passivation agent for stainless steel. Successful completion of this project will result in citric acid being qualified for use as an environmentally preferable alternative to nitric acid for passivation of stainless steel alloys in NASA and DoD applications.

  4. Large-scale production of anhydrous nitric acid and nitric acid solutions of dinitrogen pentoxide

    DOEpatents

    Harrar, Jackson E.; Quong, Roland; Rigdon, Lester P.; McGuire, Raymond R.

    2001-01-01

    A method and apparatus are disclosed for a large scale, electrochemical production of anhydrous nitric acid and N.sub.2 O.sub.5. The method includes oxidizing a solution of N.sub.2 O.sub.4 /aqueous-HNO.sub.3 at the anode, while reducing aqueous HNO.sub.3 at the cathode, in a flow electrolyzer constructed of special materials. N.sub.2 O.sub.4 is produced at the cathode and may be separated and recycled as a feedstock for use in the anolyte. The process is controlled by regulating the electrolysis current until the desired products are obtained. The chemical compositions of the anolyte and catholyte are monitored by measurement of the solution density and the concentrations of N.sub.2 O.sub.4.

  5. Nitric acid-formic acid compatibility in DWPF

    SciTech Connect

    Eibling, R.E.

    1992-10-20

    The addition of the Nitric Acid Flowsheet to the DWPF feed preparation process introduces nitric acid into a vessel which will subsequently receive a formic acid solution. The combination of these two acids suggests that a denitration reaction might occur. This memorandum reviews the conditions under which a denitration reaction is possible and compares these conditions to DWPF operating conditions.

  6. Revised reference model for nitric acid

    NASA Technical Reports Server (NTRS)

    Gille, J. C.; Bailey, P. L.; Craig, C. A.

    1993-01-01

    A nearly global set of data on the nitric acid distribution was obtained for seven months by the Limb Infrared Monitor of the Stratosphere (LIMS) experiment on the Nimbus 7 spacecraft. The evaluation of the accuracy, precision, and resolution of these data is described, and a description of the major features of the nitric acid distributions is presented. The zonal mean for nitric acid is distributed in a stratospheric layer that peaks near 30 mb, with the largest mixing ratios occurring in polar regions, especially in winter.

  7. Revised reference model for nitric acid

    NASA Astrophysics Data System (ADS)

    Gille, J. C.; Bailey, P. L.; Craig, C. A.

    A nearly global set of data on the nitric acid distribution was obtained for seven months by the Limb Infrared Monitor of the Stratosphere (LIMS) experiment on the Nimbus 7 spacecraft. The evaluation of the accuracy, precision and resolution of these data is described, and a description of the major features of the nitric acid distributions is presented. The zonal mean for nitric acid is distributed in a stratospheric layer that peaks near 30 mb, with the largest mixing ratios occurring in polar regions, especially in winter.

  8. Revised reference model for nitric acid

    NASA Technical Reports Server (NTRS)

    Gille, J. C.; Bailey, P. L.; Craig, C. A.

    1989-01-01

    A nearly global set of data on the nitric acid distribution was obtained for seven months by the Limb Infrared Monitor of the Stratosphere (LIMS) experiment on the Nimbus 7 spacecraft. The evaluation of the accuracy, precision, and resolution of these data is described, and a description of the major features of the nitric acid distributions is presented. The zonal mean for nitric acid is distributed in a stratospheric layer that peaks near 30 mb, with the largest mixing ratios occurring in polar regions, especially in winter.

  9. ELECTROLYTIC REDUCTION OF NITRIC ACID SOLUTIONS

    DOEpatents

    Alter, H.W.; Barney, D.L.

    1958-09-30

    A process is presented for the treatment of radioactivc waste nitric acid solutions. The nitric acid solution is neutralized with an alkali metal hydroxide in an amount sufficient to precipitate insoluble hydroxides, and after separation of the precipitate the solution is electrolyzed to convert the alkali nitrate formed, to alkali hydroxide, gaseous ammonla and oxygen. The solution is then reusable after reducing the volume by evaporating the water and dissolved ammonia.

  10. Chemical of the Month: Nitric Acid.

    ERIC Educational Resources Information Center

    Pannu, Sardul S.

    1984-01-01

    Presents background information on nitric acid including old names, history, occurrence, methods of preparation, uses, production, and price. Includes such chemical properties as decomposition; acidity, oxidation of metals and nonmetals; reactions with organic and inorganic compounds; gaseous fluorine; and nitrating properties. Also discusses bond…

  11. Ab initio molecular dynamics simulation of aqueous solution of nitric oxide in different formal oxidation states

    NASA Astrophysics Data System (ADS)

    Venâncio, Mateus F.; Rocha, Willian R.

    2015-10-01

    Ab initio molecular dynamics simulations were used to investigate the early chemical events involved in the dynamics of nitric oxide (NOrad), nitrosonium cation (NO+) and nitroxide anion (NO-) in aqueous solution. The NO+ ion is very reactive in aqueous solution having a lifetime of ∼4 × 10-13 s, which is shorter than the value of 3 × 10-10 s predicted experimentally. The NO+ reacts generating the nitrous acid as an intermediate and the NO2- ion as the final product. The dynamics of NOrad revealed the reversibly formation of a transient anion radical species HONOrad -.

  12. Containment of nitric acid solutions of Plutonium-238

    NASA Astrophysics Data System (ADS)

    Reimus, M. A. H.; Silver, G. L.; Pansoy-Hjelvik, L.; Ramsey, K. B.

    1999-01-01

    The corrosion of various metals that could be used to contain nitric acid solutions of Pu-238 has been studied. Tantalum and tantalum/2.5% tungsten resisted the test solvent better than 304L stainless steel and several INCONEL alloys. The solvent used to imitate nitric acid solutions of Pu-238 contained 70% nitric acid, hydrofluoric acid, and ammonium hexanitratocerate.

  13. Influence of nitric acid treatment in different media on X-ray structural parameters of coal

    SciTech Connect

    Sudip Maity; Ashim Choudhury

    2008-11-15

    The treatment of coal with nitric acid in aqueous and non-aqueous media introduces changes in the chemical and spatial structure of the organic mass. Four coals of different rank have been treated with nitric acid in aqueous and glacial acetic acid media for assessing the changes in the structural parameters by the X-ray diffraction (XRD) technique. Slow-scan XRD has been performed for the raw and treated coals, and X-ray structural parameters (d002, Lc, and Nc) and aromaticity (fa) have been determined by profile-fitting software. Considerable variation of the structural parameters has been observed with respect to the raw coals. The d002 values have decreased in aqueous medium but increased in acetic acid medium; however, Lc, Nc, and fa values have increased in aqueous medium but decreased in acetic acid medium. It is also observed that considerable oxidation takes place during nitric acid treatment in aqueous medium, but nitration is the predominant phenomenon in acetic acid medium. Disordering of the coal structure increases in acetic acid medium, but a reverse trend is observed in the aqueous medium. As a result, structurally modified coals (SMCs) are derived as new coal-derived substances. 15 refs., 6 figs., 3 tabs.

  14. Alternative to Nitric Acid Passivation Project Overview

    NASA Technical Reports Server (NTRS)

    Lewis, Pattie L.

    2013-01-01

    The standard practice for protection of stainless steel is a process called passivation. This procedure results in the formation of a metal oxide layer to prevent corrosion. Typical passivation procedures call for the use of nitric acid which exhibits excellent corrosion performance; however, there are a number of environmental, worker safety, and operational issues associated with its use. The longtime military specification for the passivation of stainless steel was cancelled in favor of newer specifications which allow for the use of citric acid in place of nitric acid. Citric acid offers a variety of benefits that include increased safety for personnel, reduced environmental impact, and reduced operational costs. There have been few studies, however, to determine whether citric acid is an acceptable alternative for NASA and DoD. This paper details activities to date including development of the joint test plan, on-going and planned testing, and preliminary results.

  15. A FURTHER EVALUATION OF MICROCOULOMETRY FOR ATMOSPHERIC NITRIC ACID MONITORING

    EPA Science Inventory

    A coulometric instrument for measuring gaseous nitric acid is modified to improve response time characteristics and simplify operation. Possible interferences were investigated and found minimal. Comparison measurements of nitric acid by long path Fourier Transform infrared analy...

  16. 49 CFR 173.158 - Nitric acid.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Nitric acid. 173.158 Section 173.158 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SHIPPERS-GENERAL REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Non-bulk Packaging...

  17. Infrared optical constants of H2O ice, amorphous nitric acid solutions, and nitric acid hydrates

    NASA Technical Reports Server (NTRS)

    Toon, Owen B.; Koehler, Birgit G.; Middlebrook, Ann M.; Tolbert, Margaret A.; Jordon, Joseph

    1994-01-01

    We determined the infrared optical constants of nitric acid trihydrate, nitric acid dihydrate, nitric acid monohydrate, and solid amorphous nitric acid solutions which crystallize to form these hydrates. We have also found the infrared optical constants of H2O ice. We measured the transmission of infrared light throught thin films of varying thickness over the frequency range from about 7000 to 500/cm at temperatures below 200 K. We developed a theory for the transmission of light through a substrate that has thin films on both sides. We used an iterative Kramers-Kronig technique to determine the optical constants which gave the best match between measured transmission spectra and those calculated for a variety of films of different thickness. These optical constants should be useful for calculations of the infrared spectrum of polar stratospheric clouds.

  18. Nitric acid in polar stratospheric clouds - Similar temperature of nitric acid condensation and cloud formation

    NASA Technical Reports Server (NTRS)

    Pueschel, Rudolf F.; Snetsinger, Kenneth G.; Hamill, Patrick; Goodman, Jindra K.; Mccormick, M. Patrick

    1990-01-01

    As shown independently by two different techniques, nitric acid aerosols and polar stratospheric clouds (PSCs) both form below similar threshold temperatures. This supports the idea that the PSC particles involved in chlorine activation and ozone depletion in the winter polar stratosphere are composed of nitric acid. One technique used to show this is the inertial impaction of nitric acid aerosols using an Er-2 aircraft; the other method is remote sensing of PSCs by the Stratospheric Aerosol Measurement (SAM II) satellite borne optical sensor. Both procedures were in operation during the Arctic Airborne Stratospheric Expedition in 1989, and the Airborne Antarctic Ozone Experiment in 1987. Analysis of Arctic particles gathered in situ indicates the presence of nitric acid below a 'first appearance' temperature Tfa = 202 K. This is the same highest temperature at which PSCs are seen by the SAM II satellite. In comparison, a 'first appearance' temperature Tfa = 198 K as found for the Antarctic samples.

  19. Metastable Nitric Acid Trihydrate in Ice Clouds

    PubMed Central

    Weiss, Fabian; Kubel, Frank; Gálvez, Óscar; Hoelzel, Markus; Parker, Stewart F.; Baloh, Philipp; Iannarelli, Riccardo; Rossi, Michel J.

    2016-01-01

    Abstract The composition of high‐altitude ice clouds is still a matter of intense discussion. The constituents in question are ice and nitric acid hydrates, but the exact phase composition of clouds and its formation mechanisms are still unknown. In this work, conclusive evidence for a long‐predicted phase, alpha‐nitric acid trihydrate (alpha‐NAT), is presented. This phase was characterized by a combination of X‐ray and neutron diffraction experiments, allowing a convincing structure solution. Furthermore, vibrational spectra (infrared and inelastic neutron scattering) were recorded and compared with theoretical calculations. A strong interaction between water ice and alpha‐NAT was found, which explains the experimental spectra and the phase‐transition kinetics. On the basis of these results, we propose a new three‐step mechanism for NAT formation in high‐altitude ice clouds. PMID:26879259

  20. Metastable Nitric Acid Trihydrate in Ice Clouds.

    PubMed

    Weiss, Fabian; Kubel, Frank; Gálvez, Óscar; Hoelzel, Markus; Parker, Stewart F; Baloh, Philipp; Iannarelli, Riccardo; Rossi, Michel J; Grothe, Hinrich

    2016-03-01

    The composition of high-altitude ice clouds is still a matter of intense discussion. The constituents in question are ice and nitric acid hydrates, but the exact phase composition of clouds and its formation mechanisms are still unknown. In this work, conclusive evidence for a long-predicted phase, alpha-nitric acid trihydrate (alpha-NAT), is presented. This phase was characterized by a combination of X-ray and neutron diffraction experiments, allowing a convincing structure solution. Furthermore, vibrational spectra (infrared and inelastic neutron scattering) were recorded and compared with theoretical calculations. A strong interaction between water ice and alpha-NAT was found, which explains the experimental spectra and the phase-transition kinetics. On the basis of these results, we propose a new three-step mechanism for NAT formation in high-altitude ice clouds. PMID:26879259

  1. Ruthenium volatility from the vitrification of melter feeds prepared using the Nitric Acid Flowsheet

    SciTech Connect

    Hutson, N.D.

    1992-10-22

    The present DWPF flowsheet calls for the chemical treatment of waste sludge with 90 wt% formic acid prior to the addition of the Precipitate Hydrolysis Aqueous (PHA) product. An alternative processing methodology, denoted the ``Nitric Acid Flowsheet``, has been proposed. In the application of this flowsheet, nitric acid would be used to neutralize sludge base components (hydroxides and carbonates) prior to the addition of late wash PHA. The late wash PHA will contain sufficient quantities of formic acid to adequately complete necessary reduction-oxidation (REDOX) reactions.

  2. An evaluation of mercury removal in the IDMS using the nitric acid flowsheet

    SciTech Connect

    Hutson, N.D.

    1992-10-22

    The present DWPF flowsheet calls for the chemical treatment of waste sludge with 90 wt % formic acid prior to the addition of the Precipitate Hydrolysis Aqueous (PHA) product. An alternative processing methodology, denoted the ``Nitric Acid Flowsheet``, has been proposed. in the application of this flowsheet, nitric acid would be used to neutralize sludge base components (hydroxides and carbonates) prior to the addition of late wash PHA. The late wash PHA will contain sufficient quantities of formic acid to adequately complete necessary reduction-oxidation (REDOX) reactions.

  3. Ruthenium volatility from the vitrification of melter feeds prepared using the Nitric Acid Flowsheet

    SciTech Connect

    Hutson, N.D.

    1992-10-22

    The present DWPF flowsheet calls for the chemical treatment of waste sludge with 90 wt% formic acid prior to the addition of the Precipitate Hydrolysis Aqueous (PHA) product. An alternative processing methodology, denoted the Nitric Acid Flowsheet'', has been proposed. In the application of this flowsheet, nitric acid would be used to neutralize sludge base components (hydroxides and carbonates) prior to the addition of late wash PHA. The late wash PHA will contain sufficient quantities of formic acid to adequately complete necessary reduction-oxidation (REDOX) reactions.

  4. An evaluation of mercury removal in the IDMS using the nitric acid flowsheet

    SciTech Connect

    Hutson, N.D.

    1992-10-22

    The present DWPF flowsheet calls for the chemical treatment of waste sludge with 90 wt % formic acid prior to the addition of the Precipitate Hydrolysis Aqueous (PHA) product. An alternative processing methodology, denoted the Nitric Acid Flowsheet'', has been proposed. in the application of this flowsheet, nitric acid would be used to neutralize sludge base components (hydroxides and carbonates) prior to the addition of late wash PHA. The late wash PHA will contain sufficient quantities of formic acid to adequately complete necessary reduction-oxidation (REDOX) reactions.

  5. Growth of nitric acid hydrates on thin sulfuric acid films

    NASA Astrophysics Data System (ADS)

    Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

    1994-05-01

    Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1 - 3 × 10-4 Torr H2O and 1 - 2.5 × 10-6 Torr HNO3) and subjected to cooling and heating cycles. FTIR spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

  6. Growth of nitric acid hydrates on thin sulfuric acid films

    NASA Technical Reports Server (NTRS)

    Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

    1994-01-01

    Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 x 10(exp -4) Torr H2O and 1-2.5 x 10(exp -6) Torr HNO3) and subjected to cooling and heating cycles. Fourier Transform Infrared (FTIR) spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

  7. An intercomparison of airborne nitric acid measurements

    NASA Astrophysics Data System (ADS)

    Gregory, G. L.; Hoell, J. M.; Huebert, B. J.; van Bramer, S. E.; Lebel, P. J.; Vay, S. A.; Marinaro, R. M.; Schiff, H. I.; Hastie, D. R.; Mackay, G. I.; Karecki, D. R.

    1990-06-01

    Results from an airborne intercomparison of techniques to measure tropospheric levels of nitric acid are discussed. The intercomparison was part of the National Aeronautics and Space Administration's Global Tropospheric Experiment and was conducted during the summer of 1986. Instruments intercompared included a denuder tube collection system (DENUDER) with chemiluminescent detection, a niylon filter collection system (FILTER) with ion chromatography detection, and a tunable diode laser (TDLAS) multipath absorption system. Intercomparison of investigators' calibration standards were also performed as part of the test protocol. While results were somewhat "soft" and data sparse, these tests suggested that the TDLAS measurements might be high compared to the other techniques. Airborne intercomparisons were conducted predominately in the free troposphere and included encounters with marine and continental air masses. While the intercomparisons included mixing ratios to 1000 parts per trillion by volume (pptv), the majority of the results were for mixing ratios of <300 pptv. The TDLAS participated in an intercomparison of NO2 instruments (major focus) that was also conducted during the same flights. As a result the TDLAS data set is limited. Further, a significant fraction of the nitric acid measurements were below the TDLAS detection limit (75 pptv as configured for these tests). While the lack of simultaneous measurements from the three instruments limits the conclusions that can be drawn, it is clear that there can be substantial disagreement among the three techniques, even at mixing ratios above their respective detection limits. Equally clear is that at mixing ratios below 150 pptv there is very little correlation between their results. Based on these observations, an overall conclusion from the intercomparison is that none of the HNO3 techniques can be identified to unambiguously (e.g., 20% accuracy) provide measurements of HNO3 at levels often encountered in the

  8. Nitric acid in polar stratospheric clouds: Similar temperature of nitric acid condensation and cloud formation

    SciTech Connect

    Pueschel, R.F.; Snetsinger, K.G. ); Hamill, P.; Goodman, J.K. ); McCormick, M.P. )

    1990-03-01

    As shown independently by two different techniques, nitric acid aerosols and polar stratospheric clouds both form below similar threshold temperatures. This supports the idea that the polar stratospheric cloud (PSC) particles involved in chlorine activation and ozone depletion in the winter polar stratosphere are composed of nitric acid. One technique used to show this is inertial impaction of nitric acid aerosols using an ER-2 aircraft; the other method is remote sensing of PSCs by the Stratospheric Aerosol Measurement (SAM II) satellite borne optical sensor. Both procedures were in operation during the Arctic Airborne Stratospheric Expedition in 1989, and the Airborne Antarctic Ozone Experiment in 1987. Analysis of Arctic particles gathered in situ indicates the presence of nitric acid below a first appearance temperature T{sub fa} = 202 K. This is the same highest temperature at which PSCs are seen by the SAM II satellite. In comparison, a first appearance temperature T{sub fa} = 198 K was found for the Antarctic samples.

  9. Metastable Nitric Acid Trihydrate in Ice Clouds

    NASA Astrophysics Data System (ADS)

    Weiss, Fabian; Kubel, Frank; Gálvez, Oscar; Hölzel, Markus; Parker, Stewart F.; Baloh, Philipp; Iannarelli, Riccardo; Rossi, Michel J.; Grothe, Hinrich

    2016-04-01

    The composition of high altitude ice clouds is still a matter of intense discussion. The constituents in question are ice and nitric acid hydrates. The identification and formation mechanisms, however, are still unknown but are essential to understand atmospheric processing such as the seasonal ozone depletion in the lower polar stratosphere or the radiation balance of planet Earth. We found conclusive evidence for a long-predicted phase, which has been named alpha nitric acid trihydrate (alpha-NAT). This phase has been proven by combination of X-ray and neutron diffraction experiments allowing a convincing structure solution. Additionally, vibrational spectra (infrared and inelastic neutron scattering) were recorded and compared with theoretical calculations. A strong affinity between water ice and alpha-NAT has been found, which explains the experimental spectra and the phase transition kinetics essential for identification in the atmosphere. On the basis of our results, we propose a new three-step mechanism for NAT-formation in high altitude ice clouds. F. Weiss et al. Angew. Chem. Int. Ed. 2016, accepted, DOI:10.1002/anie.201510841

  10. EFFECTS OF NITRIC ACID ON CRITICALITY SAFETY ANALYSIS

    SciTech Connect

    Williamson, B.

    2011-08-18

    As nitric acid molarity is increased, there are two competing phenomena affecting the reactivity of the system. First, there is interaction between each of the 10 wells in the basket-like insert. As the molarity of the nitric acid solution is increased (it moves from 100% water to 100% HNO{sub 3}), the hydrogen atom density decreases by about 80%. However, it remains a relatively efficient moderator. The moderating ratio of nitric acid is about 90% that of water. As the media between the wells is changed from 100% water to 100% nitric acid, the density of the media increases by 50%. A higher density typically leads to a better reflector. However, when the macroscopic scattering cross sections are considered, nitric acid is a much worse reflector than water. The effectiveness of nitric acid as a reflector is about 40% that of water. Since the media between the wells become a worse reflector and still remains an effective moderator, interaction between the wells increases. This phenomenon will cause reactivity to increase as nitric acid molarity increases. The seond phenomenon is due to the moderating ratio changing in the high concentration fissile-nitric acid solution in the 10 wells. Since the wells contain relatively small volumes of high concentration solutions, a small decrease in moderating power has a large effect on reactivity. This is due to the fact that neutrons are more likely to escape the high concentration fissile solution before causing another fission event. The result of this phenomenon is that as nitric acid molarity increases, reactivity decreases. Recent studies have shown that the second phenomenon is indeed the dominating force in determining reactivity changes in relation to nitric acid molarity changes. When considering the system as a whole, as nitric acid molarity increases, reactivity decreases.

  11. An intercomparison of airborne nitric acid measurements

    SciTech Connect

    Gregory, G.L.; Hoell, J.M. Jr.; LeBel, P.J.; Vay, S.A. ); Huebert, B.J. ); Van Bramer, S.E. ); Marinaro, R.M. ); Schiff, H.I.; Hastie, D.R. ); Mackay, G.I.; Karecki, D.R. )

    1990-06-20

    Instruments intercompared included a denuder tube collection system (DENUDER) with chemiluminescent detection, a nylon filter collection system (FILTER) with ion chromatography detection, and a tunable diode laser (TDLAS) multipath absorption system. While results were somewhat soft and data sparse, these tests suggested that the TDLAS measurements might be high compared to the other techniques. Airborne intercomparisons were conducted predominantly in the free troposphere and included encounters with marine and continental air masses. While the intercomparisons included mixing ratios to 1,000 parts per trillion by volume (pptv), the majority of the results were for mixing ratios of <300 pptv. While the lack of simultaneous measurements from the three instruments limits the conclusions that can be drawn, it is clear that there can be substantial disagreement among the three techniques, even at mixing ratios above their respective detection limits. Equally clear is that at mixing ratios below 150 pptv there is very little correlation between their results. Based on these observations, an overall conclusion from the intercomparison is that none of the HNO{sub 3} techniques can be identified to unambiguously (e.g., 20% accuracy) provide measurements of HNO{sub 3} at levels often encountered in the free troposphere (e.g., 100 pptv). However, at the more elevated levels of HNO{sub 3} (e.g., >150 pptv), both the FILTER and DENUDER techniques reported the same levels of nitric acid, while as suggested by the results from the standards intercomparison, the TDLAS reported higher nitric acid values than the other two techniques.

  12. Adverse experiences with nitric acid at the Savannah River Site

    SciTech Connect

    Durant, W.S.; Craig, D.K.; Vitacco, M.J.; McCormick, J.A.

    1991-06-01

    Nitric acid is used routinely at the Savannah River Site (SRS) in many processes. However, the site has experienced a number of adverse situations in handling nitric acid. These have ranged from minor injuries to personnel to significant explosions. This document compiles many of these events and includes discussions of process upsets, fires, injuries, and toxic effects of nitric acid and its decomposition products. The purpose of the publication is to apprise those using the acid that it is a potentially dangerous material and can react in many ways as demonstrated by SRS experience. 10 refs.

  13. Aqueous Photochemistry of Glyoxylic Acid.

    PubMed

    Eugene, Alexis J; Xia, Sha-Sha; Guzman, Marcelo I

    2016-06-01

    Aerosols affect climate change, the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. While the formation of secondary organic aerosols (SOA) from gas phase precursors is relatively well understood, studying aqueous chemical reactions contributing to the total SOA budget is the current focus of major attention. Field measurements have revealed that mono-, di-, and oxo-carboxylic acids are abundant species present in SOA and atmospheric waters. This work explores the fate of one of these 2-oxocarboxylic acids, glyoxylic acid, which can photogenerate reactive species under solar irradiation. Additionally, the dark thermal aging of photoproducts is studied by UV-visible and fluorescence spectroscopies to reveal that the optical properties are altered by the glyoxal produced. The optical properties display periodicity in the time domain of the UV-visible spectrum of chromophores with absorption enhancement (thermochromism) or loss (photobleaching) during nighttime and daytime cycles, respectively. During irradiation, excited state glyoxylic acid can undergo α-cleavage or participate in hydrogen abstractions. The use of (13)C nuclear magnetic resonance spectroscopy (NMR) analysis shows that glyoxal is an important intermediate produced during direct photolysis. Glyoxal quickly reaches a quasi-steady state as confirmed by UHPLC-MS analysis of its corresponding (E) and (Z) 2,4-dinitrophenylhydrazones. The homolytic cleavage of glyoxylic acid is proposed as a fundamental step for the production of glyoxal. Both carbon oxides, CO2(g) and CO(g) evolving to the gas-phase, are quantified by FTIR spectroscopy. Finally, formic acid, oxalic acid, and tartaric acid photoproducts are identified by ion chromatography (IC) with conductivity and electrospray (ESI) mass spectrometry (MS) detection and (1)H NMR spectroscopy. A reaction mechanism is proposed based on all experimental observations. PMID:27192089

  14. Nitric acid uptake by sulfuric acid solutions under stratospheric conditions - Determination of Henry's Law solubility

    NASA Technical Reports Server (NTRS)

    Reihs, Christa M.; Golden, David M.; Tolbert, Margaret A.

    1990-01-01

    The uptake of nitric acid by sulfuric acid solutions representative of stratospheric particulate at low temperatures was measured to determine the solubility of nitric acid in sulfuric acid solutions as a function of H2SO4 concentration and solution temperature. Solubilities are reported for sulfuric acid solutions ranging from 58 to 87 wt pct H2SO4 over a temperature range from 188 to 240 K, showing that, in general, the solubility of nitric acid increases with decreasing sulfuric acid concentration and with decreasing temperature. The measured solubilities indicate that nitric acid in the global stratosphere will be found predominantly in the gas phase.

  15. PROCESS FOR EXTRACTING NEPTUNIUM AND PLUTONIUM FROM NITRIC ACID SOLUTIONS OF SAME CONTAINING URANYL NITRATE WITH A TERTIARY AMINE

    DOEpatents

    Sheppard, J.C.

    1962-07-31

    A process of selectively extracting plutonium nitrate and neptunium nitrate with an organic solution of a tertiary amine, away from uranyl nitrate present in an aqueous solution in a maximum concentration of 1M is described. The nitric acid concentration is adjusted to about 4M and nitrous acid is added prior to extraction. (AEC)

  16. FPEX gamma-Radiolysis in the Presence of Nitric Acid

    SciTech Connect

    mincher

    2007-09-01

    Abstract: The solvent formulation known as FPEX (Fission Product Extraction) contains calix[4]arene-bis-(tert-octylbenzo-crown-6) (BOBCalixC6) for Cs extraction; 4,4’,(5’)-di-(t-butyldicyclohexano)-18-crown-6 (DtBuCH18C6) for Sr extraction; 1-(2,2,3,3,-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol (Cs-7SB) modifier and trioctylamine (TOA) to aid in Cs stripping, all in Isopar L diluent. This formulation has favorable extraction efficiency for Cs and Sr from acidic solution, and was investigated here for ?-radiation stability. When FPEX was irradiated in contact with aqueous nitric acid, extraction efficiency decreased only slightly when irradiated to absorbed doses as high as 200 kGy. The color of the organic phase changed to a deep yellow-orange, and several new peaks related to radiolysis of the Cs-7SB modifier were detected by GC-ECD analysis. This had little effect on solvent extraction distribution ratios. Possible reasons for this unexpected robustness under conditions of high radiation and acidity are discussed.

  17. Nitro-linolenic acid is a nitric oxide donor.

    PubMed

    Mata-Pérez, Capilla; Sánchez-Calvo, Beatriz; Begara-Morales, Juan C; Carreras, Alfonso; Padilla, María N; Melguizo, Manuel; Valderrama, Raquel; Corpas, Francisco J; Barroso, Juan B

    2016-07-01

    Nitro-fatty acids (NO2-FAs), which are the result of the interaction between reactive nitrogen species (RNS) and non-saturated fatty acids, constitute a new research area in plant systems, and their study has significantly increased. Very recently, the endogenous presence of nitro-linolenic acid (NO2-Ln) has been reported in the model plant Arabidopsis thaliana. In this regard, the signaling role of this molecule has been shown to be key in setting up a defense mechanism by inducing the chaperone network in plants. Here, we report on the ability of NO2-Ln to release nitric oxide (NO) in an aqueous medium with several approaches, such as by a spectrofluorometric probe with DAF-2, the oxyhemoglobin oxidation method, ozone chemiluminescence, and also by confocal laser scanning microscopy in Arabidopsis cell cultures. Jointly, this ability gives NO2-Ln the potential to act as a signaling molecule by the direct release of NO, due to its capacity to induce different changes mediated by NO or NO-related molecules such as nitration and S-nitrosylation or by the electrophilic capacity of these molecules through a nitroalkylation mechanism. PMID:27164295

  18. Nitric acid recycling and copper nitrate recovery from effluent.

    PubMed

    Jô, L F; Marcus, R; Marcelin, O

    2014-01-01

    The recycling of nitric acid and copper nitrate contained in an industrial effluent was studied. The experiments conducted on such a medium showed that the presence of copper nitrate significantly improves nitric acid-water separation during distillation in an azeotropic medium. At the temperature of the azeotrope, however, this metal salt starts to precipitate, making the medium pasty, thus inhibiting the nitric acid extraction process. The optimisation of parameters such as column efficiency and adding water to the boiler at the azeotrope temperature are recommended in this protocol in order to collect the various components while avoiding the formation of by-products: NOx compounds. Thus, the absence of column, along with the addition of a small volume of water at a temperature of 118 °C, significantly increases the yield, allowing 94 % nitric acid to be recovered at the end of the process, along with the residual copper nitrate. The resulting distillate, however, is sufficiently dilute to not be used as is. Rectification is required to obtain concentrated nitric acid at 15 mol·l(-1), along with a weakly acidic distillate from the distillation front. This latter is quenched using potassium hydroxide and is used as a fertiliser solution for horticulture or sheltered market gardening. This process thus allows complete recycling of all the medium's components, including that of the distillate resulting from the nitric acid rectification operation. PMID:24627202

  19. Volatilization of iodine from nitric acid using peroxide

    DOEpatents

    Cathers, G.I.; Shipman, C.J.

    1975-10-21

    A method for removing radioactive iodine from nitric acid solution by adding hydrogen peroxide to the solution while concurrently holding the solution at the boiling point and distilling hydrogen iodide from the solution is reported.

  20. The Iron-Catalyzed Oxidation of Hydrazine by Nitric Acid

    SciTech Connect

    Karraker, D.G.

    2001-07-17

    To assess the importance of iron to hydrazine stability, the study of hydrazine oxidation by nitric acid has been extended to investigate the iron-catalyzed oxidation. This report describes those results.

  1. Formation of nitric acid hydrates - A chemical equilibrium approach

    NASA Technical Reports Server (NTRS)

    Smith, Roland H.

    1990-01-01

    Published data are used to calculate equilibrium constants for reactions of the formation of nitric acid hydrates over the temperature range 190 to 205 K. Standard enthalpies of formation and standard entropies are calculated for the tri- and mono-hydrates. These are shown to be in reasonable agreement with earlier calorimetric measurements. The formation of nitric acid trihydrate in the polar stratosphere is discussed in terms of these equilibrium constants.

  2. Absorption of nitric oxide into aqueous solutions of ferrous chelates accompanied by instantaneous reaction

    SciTech Connect

    Demmink, J.F.; Gils, I.C.F. van; Beenackers, A.A.C.M.

    1997-11-01

    The absorption of nitric oxide (NO) into aqueous solutions of ferrous chelates of nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), hydroxyethylenediaminetriacetic acid (HEDTA), and diethylenetriaminepentaacetic acid (DTPA) was studied in a stirred cell reactor. The absorption leads to stable ferrous NO chelates. Due to the high reaction rate, in combination with the relatively high P{sub NO} applied, the absorption rate is strongly affected by mass transfer limitation only. By applying penetration theory, the ratio of the diffusion coefficients of ferrous chelates and NO was determined. At elevated T, (D{sub Fe(II)chelate}/D{sub NO}){sup 1/2} decreases due to the unusual T-dependency of D{sub NO}. For ferrous NTA, the formation of the ferrous NO chelate is accompanied by pH effects that can be understood from iron chelate chemistry. In the case of ferrous NTA, pH < 5, or an excess of ligand, these effects lead to local pH gradients at the gas-liquid interface, that substantially affect the NO absorption rates. Kinetic data from the literature on the absorption of NO into ferrous chelates were evaluated using the mass transfer parameters determined. These kinetic data are often unreliable.

  3. Hydrogen generation in SRAT with nitric acid and late washing flowsheets

    SciTech Connect

    Hsu, C.W.

    1992-10-26

    Recently, SRTC recommended two process changes: (1) a final wash of the tetraphenylborate precipitate feed slurry and (2) the use of nitric acid to neutralize the sludge in the SRAT. The first change produced an aqueous hydrolysis product (PHA) with higher formic acid/formate and copper concentration, and reduced the nitrate content in the PHA by an order of magnitude. The second change is to substitute part of formic acid added to the SRAT with nitric acid, and therefore may reduce the hydrogen generated in the SRAT as well as provide nitrate as an oxidant to balance the redox state of the melter feed. The purpose of this report is to determine the pertinent variables that could affect the hydrogen generation rate with these process changes.

  4. Surface morphology study of Zr-based amorphous alloys after immersion in boiling nitric acid medium

    NASA Astrophysics Data System (ADS)

    Sharma, Poonam; Dhawan, Anil; Sharma, S. K.

    2016-05-01

    Weight loss studies have been performed to determine the corrosion resistance of amorphous Zr60Nb2Al10Ni8Cu20 and Zr59Nb3Al10Ni8Cu20 alloys in aqueous HNO3 media at boiling temperature. The FESEM micrographs has been obtained to know the surface morphology of specimens after immersion in 11.5M boiling aqueous HNO3 media. Zr59Nb3Al10Ni8Cu20 alloy shows better corrosion resistance in nitric acid media than Zr60Nb2Al10Ni8Cu20 alloy.

  5. Tested Demonstrations: Color Oscillations in the Formic Acid-Nitric Acid-Sulfuric Acid System.

    ERIC Educational Resources Information Center

    Raw, C. J. G.; And Others

    1983-01-01

    Presented are procedures for demonstrating the production of color oscillations when nitric acid is added to a formic acid/concentrated sulfuric acid mixture. Because of safety considerations, "Super-8" home movie of the color changes was found to be satisfactory for demonstration purposes. (JN)

  6. Aqueous phase nitric oxide detection by an amine-decorated metal-organic framework.

    PubMed

    Desai, Aamod V; Samanta, Partha; Manna, Biplab; Ghosh, Sujit K

    2015-04-11

    Selective and sensitive aqueous phase nitric oxide (NO) detection has been demonstrated by implementing an unsophisticated approach of ligand modulation in a porous, robust metal-organic framework (MOF). The detection is achieved through deamination by NO in an amine-decorated luminescent MOF. This is the first report of employing a physiologically stable, functionalized MOF as a NO sensor. PMID:25744379

  7. Nitric acid flowsheet with late wash PHA testing. Task Technical Plan, Integrated DWPF Melter System

    SciTech Connect

    Zamecnik, J.R.

    1993-10-28

    This Task Technical Plan outlines the activities to be conducted in the Integrated DWPF Melter System (IDMS) in ongoing support of the Defense Waste Processing Facility (DWPF) Chemical Process Cell (CPC) utilizing the Nitric Acid Flowsheet in the Sludge Receipt and Adjustment Tank (SRAT) and Precipitate Hydrolysis Aqueous (PHA) produced by the Late Wash Flowsheet. The IDMS facility is to be operated over a series of runs (2 to 4) using the Nitric Acid Flowsheet. The PHA will be produced with the Late Wash Flowsheet in the Precipitate Hydrolysis Experimental Facility (PHEF). All operating conditions shall simulate the expected DWPF operating conditions as closely as possible. The task objectives are to perform at least two IDMS runs with as many operating conditions as possible at nominal DWPF conditions. The major purposes of these runs are twofold: verify that the combined Late Wash and Nitric Acid flowsheets produce glass of acceptable quality without additional changes to process equipment, and determine the reproducibility of data from run to run. These runs at nominal conditions will be compared to previous runs made with PHA produced from the Late Wash flowsheet and with the Nitric Acid flowsheet in the SRAT (Purex 4 and Purex 5).

  8. Nitric acid measurements in connection with corrosion studies

    NASA Astrophysics Data System (ADS)

    Ferm, Martin; De Santis, Franco; Varotsos, Costas

    Atmospheric nitric acid does not only contribute to acidification and eutrophication but causes also deterioration of many materials. Material belonging to our cultural heritage is irreplaceable and its lifetime can depend on the corrosion rate. Nowadays, only very few long-term measurements of nitric acid concentration in Europe and elsewhere have been published so far. Due to the fact that atmospheric corrosion is a long-term effect, the relevant research does not necessarily require monitoring of nitric acid on a daily basis. Moreover, power supply is often not available at sites where it is of interest to study the corrosion rate of objects belonging to our cultural heritage. Besides, such measurements must not disturb the impression of the objects. In this context, the diffusive sampling technique provides average concentrations over long-term periods at a low cost. In addition, the samplers used are noiseless, comparatively small in size, and thus, their ambient exposure can be made inconspicuously and with discretion. The present paper is focussed on an intensive corrosion study, which was performed at 11 rural and 23 urban sites in Europe and one rural site in Canada during 2002/2003. For the above-mentioned reasons, the diffusive sampler's technique was employed for the nitric acid monitoring, where the diffusive samplers were first tested against the denuder technique and bi-monthly measurements of nitric acid were thus obtained. The bi-monthly concentrations varied from 0.05 to 4.3 μg m -3 and the annual averages from 0.16 to 2.0 μg m -3. The observations collected, depicted a summertime maximum and a wintertime minimum in the nitric acid concentrations, except at the northern rural sites, where a maximum in the winter was observed. Furthermore, the observed nitric acid concentrations in Southern Europe were higher than in Northern Europe. In a few places, close to the sites of urban measurements, rural measurements of nitric acid were also performed

  9. Energetic particle-induced enhancements of stratospheric nitric acid

    NASA Technical Reports Server (NTRS)

    Aikin, Arthur C.

    1994-01-01

    Inclusion of complete ion chemistry in the calculation of minor species production during energetic particle deposition events leads to significant enhancement in the calculated nitric acid concentration during precipitation. An ionization rate of 1.2 x 10(exp 3)/cu cm/s imposed for 1 day increases HNO3 from 3 x 10(exp 5) to 6 x 10(exp 7)/cu cm at 50 km. With an ionization rate of 600 cu cm/s, the maximum HNO3 is 3 x 10(exp 7)/cu cm. Calculations which neglect negative ions predict the nitric acid will fall during precipitation events. The decay time for converting HNO3 into odd nitrogen and hydrogen is more than 1 day for equinoctial periods at 70 deg latitude. Examination of nitric acid data should yield important information on the magnitude and frequency of charged particle events.

  10. Vapor-liquid equilibria for nitric acid-water and plutonium nitrate-nitric acid-water solutions

    SciTech Connect

    Maimoni, A.

    1980-01-01

    The liquid-vapor equilibrium data for nitric acid and nitric acid-plutnonium nitrate-water solutions were examined to develop correlations covering the range of conditions encountered in nuclear fuel reprocessing. The scanty available data for plutonium nitrate solutions are of poor quality but allow an order of magnitude estimate to be made. A formal thermodynamic analysis was attempted initially but was not successful due to the poor quality of the data as well as the complex chemical equilibria involved in the nitric acid and in the plutonium nitrate solutions. Thus, while there was no difficulty in correlating activity coefficients for nitric acid solutions over relatively narrow temperature ranges, attempts to extend the correlations over the range 25/sup 0/C to the boiling point were not successful. The available data were then analyzed using empirical correlations from which normal boiling points and relative volatilities can be obtained over the concentration ranges 0 to 700 g/l Pu, 0 to 13 M nitric acid. Activity coefficients are required, however, if estimates of individual component vapor pressures are needed. The required ternary activity coefficients can be approximated from the correlations.

  11. Distribution of zirconium in petroleum sulfoxides during extraction and sorption from nitric and hydrochloric acid solutions

    SciTech Connect

    Turanov, A.N.

    1988-11-20

    Petroleum sulfoxides (PSO) are effective extractants for several metals. We discussed the distribution of petroleum sulfoxides and zirconium between aqueous solutions of hydrochloric and nitric acid and organic solvents, and also the macroporous sorbent impregnated with PSO. For the investigation we used a macroposous copolymer of styrene with divinylbenzene. Our investigation showed a noticeable decrease in the contamination of the raffinates by petroleum sulfoxides and their more complete utilization as extractant of metals from solutions of acids when PSO is deposited on a macroporous copolymer of styrene with divinylbenzene.

  12. Refractory Oxide Coatings on Titanium for Nitric Acid Applications

    NASA Astrophysics Data System (ADS)

    Ravi Shankar, A.; Kamachi Mudali, U.

    2014-07-01

    Tantalum and Niobium have good corrosion resistance in nitric acid as well as in molten chloride salt medium encountered in spent fuel nuclear reprocessing plants. Commercially, pure Ti (Cp-Ti) exhibits good corrosion resistance in nitric acid medium; however, in vapor condensates of nitric acid, significant corrosion was observed. In the present study, a thermochemical diffusion method was pursued to coat Ta2O5, Nb2O5, and Ta2O5 + Nb2O5 on Ti to improve the corrosion resistance and enhance the life of critical components in reprocessing plants. The coated samples were characterized by XRD, SEM, EDX, profilometry, micro-scratch test, and ASTM A262 Practice-C test in 65 pct boiling nitric acid. The SEM micrograph of the coated samples showed that uniform dense coating containing Ta2O5 and/or Nb2O5 was formed. XRD patterns indicated the formation of TiO2, Ta2O5/Nb2O5, and mixed oxide/solid solution phase on coated Ti samples. ASTM A262 Practice-C test revealed reproducible outstanding corrosion resistance of Ta2O5-coated sample in comparison to Nb2O5- and Ta2O5 + Nb2O5-coated sample. The hardness of the Ta2O5-coated Cp-Ti sample was found to be twice that of uncoated Cp-Ti. The SEM and XRD results confirmed the presence of protective oxide layer (Ta2O5, rutile TiO2, and mixed phase) on coated sample which improved the corrosion resistance remarkably in boiling liquid phase of nitric acid compared to uncoated Cp-Ti and Ti-5Ta-1.8Nb alloy. Three phase corrosion test conducted on Ta2O5-coated samples in boiling 11.5 M nitric acid showed poor corrosion resistance in vapor and condensate phases of nitric acid due to poor adhesion of the coating. The adhesive strength of the coated samples needs to be optimized in order to improve the corrosion resistance in vapor and condensate phases of nitric acid.

  13. Diglycolamic acid modified silica gel for the separation of hazardous trivalent metal ions from aqueous solution.

    PubMed

    Suneesh, A S; Syamala, K V; Venkatesan, K A; Antony, M P; Vasudeva Rao, P R

    2015-01-15

    The surface of the silica gel was modified with diglycolamic acid moieties and the product (Si-DGAH) was characterized by elemental analysis, TG-DTA, (1)H and (29)Si NMR and scanning electron microscopy (SEM). The adsorption behavior of hazardous americium (III) and europium (III) in Si-DGAH was studied from aqueous nitric acid medium to examine the feasibility using the modified silica for the separation of Am(III) and Eu(III) from aqueous wastes. In this context, the effect of various parameters such as the duration of equilibration, and concentrations of europium, nitric acid, sodium nitrate and diethylenetriaminepentaacetic acid (DTPA) in aqueous phase, on the distribution coefficient (K(d)) of Am(III) and Eu(III) was investigated. The distribution coefficient of ∼10(3) mL/g (>99.9% extraction) was obtained for both Am(III) and Eu(III) at pH 3, and the K(d) values decreased with increase in the concentration of nitric acid. Rapid kinetics of extraction in the initial stages of equilibration, followed by the establishment of equilibrium occurred within 30 min. The extraction data were fitted into Langmuir adsorption model and the apparent europium extraction capacity was determined. Europium loading capacity of the sorbent was determined at various feed pH by column method. The study indicated the possibility of using diglycolamic acid-modified silica for the separation of Eu(III) and Am(III) from aqueous wastes. PMID:25454425

  14. Aqueous nitrite ion determination by selective reduction and gas phase nitric oxide chemiluminescence

    NASA Technical Reports Server (NTRS)

    Dunham, A. J.; Barkley, R. M.; Sievers, R. E.; Clarkson, T. W. (Principal Investigator)

    1995-01-01

    An improved method of flow injection analysis for aqueous nitrite ion exploits the sensitivity and selectivity of the nitric oxide (NO) chemilluminescence detector. Trace analysis of nitrite ion in a small sample (5-160 microL) is accomplished by conversion of nitrite ion to NO by aqueous iodide in acid. The resulting NO is transported to the gas phase through a semipermeable membrane and subsequently detected by monitoring the photoemission of the reaction between NO and ozone (O3). Chemiluminescence detection is selective for measurement of NO, and, since the detection occurs in the gas-phase, neither sample coloration nor turbidity interfere. The detection limit for a 100-microL sample is 0.04 ppb of nitrite ion. The precision at the 10 ppb level is 2% relative standard deviation, and 60-180 samples can be analyzed per hour. Samples of human saliva and food extracts were analyzed; the results from a standard colorimetric measurement are compared with those from the new chemiluminescence method in order to further validate the latter method. A high degree of selectivity is obtained due to the three discriminating steps in the process: (1) the nitrite ion to NO conversion conditions are virtually specific for nitrite ion, (2) only volatile products of the conversion will be swept to the gas phase (avoiding turbidity or color in spectrophotometric methods), and (3) the NO chemiluminescence detector selectively detects the emission from the NO + O3 reaction. The method is free of interferences, offers detection limits of low parts per billion of nitrite ion, and allows the analysis of up to 180 microL-sized samples per hour, with little sample preparation and no chromatographic separation. Much smaller samples can be analyzed by this method than in previously reported batch analysis methods, which typically require 5 mL or more of sample and often need chromatographic separations as well.

  15. NITRIC ACID SHOOTOUT: FIELD COMPARISON OF MEASUREMENT METHODS (JOURNAL VERSION)

    EPA Science Inventory

    Eighteen instruments for measuring atmospheric concentrations of nitric acid were compared in an eight-day field study at Pomona College, situated in the eastern portion of the Los Angeles Basin, in September 1985. The study design included collocated and separated duplicate samp...

  16. The Nitric Acid Oxidation of Selected Alcohols and Ketones.

    ERIC Educational Resources Information Center

    Field, Kurt W.; And Others

    1985-01-01

    Shows that nitric acid can be used as a rapid, versatile, and economical oxidant for selected organic substances. The experiments (with background information, procedures, and results provided) require one three-hour laboratory period but could serve as open-ended projects since substrates not described could be oxidized. (JN)

  17. The nitric acid burn trauma of the skin.

    PubMed

    Kolios, L; Striepling, E; Kolios, G; Rudolf, K-D; Dresing, K; Dörges, J; Stürmer, K M; Stürmer, E K

    2010-04-01

    Nitric acid burn traumata often occur in the chemical industry. A few publications addressing this topic can be found in the medical database, and there are no reports about these traumata in children. A total of 24 patients, average 16.6 years of age, suffering from nitric acid traumata were treated. Wound with I degrees burns received open therapy with panthenol-containing creams. Wound of II degrees and higher were initially treated by irrigation with sterile isotonic saline solution and then by covering with silver-sulphadiazine dressing. Treatment was changed on the second day to fluid-absorbent foam bandages for superficial wounds (up to IIa degrees depth) and occlusive, antiseptic moist bandages in combination with enzymatic substances for IIb degrees -III degrees burns. After the delayed demarcation, necrectomy and mesh-graft transplantation were performed. All wounds healed adequately. Chemical burn traumata with nitric acid lead to specific yellow- to brown-stained wounds with slower accumulation of eschar and slower demarcation compared with thermal burns. Remaining wound eschar induced no systemic inflammation reaction. After demarcation, skin transplantation can be performed on the wounds, as is commonly done. The distinguishing feature of nitric-acid-induced chemical burns is the difficulty in differentiation and classification of burn depth. An immediate lavage should be followed by silver sulphadiazine treatment. Thereafter, fluid-absorbent foam bandages or occlusive, antiseptic moist bandages should be used according to the burn depth. Slow demarcation caused a delay in performing surgical treatments. PMID:19875347

  18. Nitroaromatic amino acids as inhibitors of neuronal nitric oxide synthase.

    PubMed

    Cowart, M; Kowaluk, E A; Daanen, J F; Kohlhaas, K L; Alexander, K M; Wagenaar, F L; Kerwin, J F

    1998-07-01

    Nitric oxide (NO.) is an important biomodulator of many physiological processes. The inhibition of inappropriate production of NO. by the isoforms of nitric oxide synthase (NOS) has been proposed as a therapeutic approach for the treatment of stroke, inflammation, and other processes. In this study, certain 2-nitroaryl-substituted amino acid analogues were discovered to inhibit NOS. Analogues bearing a 5-methyl substituent on the aromatic ring demonstrated maximal inhibitory potency. For two selected inhibitors, investigation of the kinetics of the enzyme showed the inhibition to be competitive with l-arginine. Additionally, functional NOS inhibition in tissue preparations was demonstrated. PMID:9651169

  19. Isothermal heat measurements of TBP-nitric acid solutions

    SciTech Connect

    Smith, J.R.; Cavin, W.S.

    1994-12-16

    Net heats of reaction were measured in an isothermal calorimeter for both single phase (organic) and two phase (organic and aqueous) TBP/HNO{sub 3} reacting solutions at temperatures above 100 C. The oxidation rate constant was determined to be 5.4E-4 min{sup {minus}1} at 110 C for an open ``vented`` system as compared to 1.33 E-3 min{sup {minus}1} in the closed system. The heat released per unit material oxidized was also reduced. The oxidation in both phases was found to be first order in nitric acid and pseudo-zero order in butylnitrate and water. The hydrolysis (esterification) rate constant determined by Nichols` (1.33E-3 min{sup {minus}1}) fit the experimental data from this work well. Forced evaporation of the volatile components by the product gases from oxidation resulted in a cooling mechanism which more than balanced the heat from the oxidation reaction in the two-phased systems. Rate expressions were derived and rate constants determined for both the single and two phase systems. An approximating mathematical model was developed to fit the experimental data and to extrapolate beyond the experimental conditions. This model shows that one foot of ``reacting`` 14.3M HNO{sub 3} aqueous phase solution at 121 C will transport sufficient water to the organic phase to replace evaporative losses, maintaining endothermicity, for organic layers up to 12.2 + 6.0 feet deep. If the pressure in a reacting system is allowed to increase due to insufficient venting the temperature of the organic phase would increase in temperature to reach a new equilibrium. The rate of oxidation would increase not only due to the increase in temperature but also from the increased concentration of dissolved HNO{sub 3} reduction products. Another important factor is that the cooling system described in this work becomes less effective as the total pressure increases. These factors probably contributed to the explosion at Tomsk.

  20. Nitric acid catalyzed hydrolysis of SO3 in the formation of sulfuric acid: A theoretical study

    NASA Astrophysics Data System (ADS)

    Long, Bo; Chang, Chun-Ran; Long, Zheng-Wen; Wang, Yi-Bo; Tan, Xing-Feng; Zhang, Wei-Jun

    2013-08-01

    The gas-phase hydrolysis of SO3 in the presence of one water molecule, two water molecules, and nitric acid is investigated utilizing high level quantum chemical methods and transition state theory. The calculated results demonstrate that nitric acid exerts a strong catalytic role in the hydrolysis of SO3 because the activated barrier of hydrolysis of SO3 with the assistance of nitric acid is reduced to about 3.7 kcal/mol, which is about 20 kcal/mol lower than that of the SO3 reaction with water relative to the respective pre-reactive complex.

  1. AMERICIUM SEPARATIONS FROM NITRIC ACID PROCESS EFFLUENT STREAMS

    SciTech Connect

    M. BARR; G. JARVINEN; ET AL

    2000-08-01

    The aging of the US nuclear stockpile presents a number of challenges, including the ever-increasing radioactivity of plutonium residues from {sup 241}Am. Minimization of this weak gamma-emitter in process and waste solutions is desirable to reduce both worker exposure and the effects of radiolysis on the final waste product. Removal of americium from plutonium nitric acid processing effluents, however, is complicated by the presence of large.quantities of competing metals, particularly Fe and Al, and-strongly oxidizing acidic solutions. The reprocessing operation offers several points at which americium removal maybe attempted, and we are evaluating two classes of materials targeted at different steps in the process. Extraction chromatography resin materials loaded with three different alkylcarbamoyl phosphinates and phosphine oxides were accessed for Am removal efficiency and Am/Fe selectivity from 1-7 molar nitric acid solutions. Commercial and experimental mono- and bifunctional anion-exchange resins were evaluated for total alpha-activity removal from post-evaporator solutions whose composition, relative to the original nitric acid effluent, is reduced in acid and greatly increased in total salt content. With both classes of materials, americium/total alpha emission removal is sufficient to meet regulatory requirements even under sub-optimal conditions. Batch distribution coefficients, column performance data, and the effects of Fe-masking agents will be presented.

  2. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    SciTech Connect

    Pierce, R.

    2012-02-22

    HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into the H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. For 6 M HNO{sub 3}, 10.5 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2 g/L and 0.25 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}.

  3. Reactivity of Resorcinol Formaldehyde Resin with Nitric Acid

    SciTech Connect

    King, William D.; Fondeur, Fernando F.; Wilmarth, William R.; Pettis, Myra E.

    2005-10-25

    Solid-state infrared spectroscopy, differential scanning calorimetry, and elemental analysis have been used to evaluate the reactivity of resorcinol formaldehyde resin with nitric acid and characterize the solid product. Two distinct reactions were identified within the temperature range 25-55 C. The first reaction is primarily associated with resin nitration, while the second involves bulk oxidation and degradation of the polymer network leading to dissolution and off-gassing. The threshold conditions promoting reaction have been identified. Reaction was confirmed with nitric acid concentrations as low as 3 M at 25 C applied temperature and 0.625 M at 66 C. Although a nitrated resin product can be isolated under appropriate experimental conditions, calorimetry testing indicates no significant hazard associated with handling the dry material.

  4. REACTIVITY OF RESORCINOL FORMALDEHYDE RESIN WITH NITRIC ACID

    SciTech Connect

    King, W; Fernando Fondeur, F; Bill Wilmarth, B; Myra Pettis, M; Shirley Mccollum, S

    2006-06-14

    Solid-state infrared spectroscopy, differential scanning calorimetry, and elemental analysis have been used to evaluate the reactivity of resorcinol formaldehyde resin with nitric acid and characterize the solid product. Two distinct reactions were identified within the temperature range 25-55 C. The first reaction is primarily associated with resin nitration, while the second involves bulk oxidation and degradation of the polymer network leading to dissolution and off-gassing. Reaction was confirmed with nitric acid concentrations as low as 3 M at 25 C applied temperature and 0.625 M at 66 C. Although a nitrated resin product can be isolated under appropriate experimental conditions, calorimetry testing indicates no significant hazard associated with handling the dry material.

  5. Stress corrosion cracking of zirconium in hot nitric acid

    SciTech Connect

    Kajimura, H.; Nagano, H. )

    1992-05-01

    Zirconium (Zr) has excellent general corrosion resistance in nitric acid. However, stress corrosion cracking (SCC) has been reported in concentrated nitric acid. The purpose of this paper is to evaluate the SCC susceptibility of Zr as a function of HNO[sub 3] concentration, from 6 to 94%, and temperature. The SCC mechanism was also investigated in relation to the electrochemical behavior. The slow strain rate test technique, under constant potential conditions, was mainly adopted for SCC testing. SCC did not occur in the boiling HNO[sub 3] at concentrations less than 70% unless an anodic potential was applied. The critical SCC potential, which coincides with the transient potential from passive to transpassive behavior in the polarization curve, decreased with an increase in HNO[sub 3] concentration. In boiling 94% HNO[sub 3] Zr exhibited SCC even under open-circuit potential conditions.

  6. Mercury-free dissolution of aluminum-clad fuel in nitric acid

    DOEpatents

    Christian, J.D.; Anderson, P.A.

    1994-11-15

    A mercury-free dissolution process for aluminum involves placing the aluminum in a dissolver vessel in contact with nitric acid-fluoboric acid mixture at an elevated temperature. By maintaining a continuous flow of the acid mixture through the dissolver vessel, an effluent containing aluminum nitrate, nitric acid, fluoboric acid and other dissolved components are removed. 5 figs.

  7. Mercury-free dissolution of aluminum-clad fuel in nitric acid

    DOEpatents

    Christian, Jerry D.; Anderson, Philip A.

    1994-01-01

    A mercury-free dissolution process for aluminum involves placing the aluminum in a dissolver vessel in contact with nitric acid-fluoboric acid mixture at an elevated temperature. By maintaining a continuous flow of the acid mixture through the dissolver vessel, an effluent containing aluminum nitrate, nitric acid, fluoboric acid and other dissolved components are removed.

  8. Nylon Dissolution in Nitric Acid Solutions

    SciTech Connect

    KESSINGER, GLENF.

    2004-06-16

    H Area Operations is planning to process Pu-contaminated uranium scrap in support of de-inventory efforts. Nylon bags will be used to hold materials to be dissolved in H-Canyon. Based on this set of twelve nylon dissolutions, it is concluded that (when other variables are held constant): increased acid concentration results in increased dissolution rates; increased acid concentration results in a lower dissolution onset temperature; little, if any, H plus is consumed during the depolymerization process; and 2.0-3.0 M HNO3, with 0.025 M KF and 2 g/L B, is satisfactory for the dissolution of nylon bag materials to be used during H-Canyon processing.

  9. Interactions of Gaseous Nitric Acid with Surfaces of Environmental Interest

    SciTech Connect

    Dubowski, Y; Sumner, Ann Louise; Menke, E J.; Gaspar, Dan J.; Newberg, J T.; Hoffman, Rachel C.; Penner, R M.; Hemminger, J C.; Finlayson-Pitts, Barbara J.

    2004-07-21

    Gaseous nitric acid removal by surfaces in experimental systems and in the atmospheric boundary layer is rapid. However, neither the form of HNO? on surfaces nor its impact on the properties of the thin surface film are known. We report here studies of surfaces that have been exposed at room temperature (295 ? 2 K) to gaseous mixtures of water vapor with HNO? at concentrations from 46 ppb to 4 x 10? ppm. The surfaces were probed using a combination of Fourier transform infrared spectrometry (FTIR), non-contact atomic force microscopy (AFM), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and X-ray photoelectron spectroscopy (XPS). Exposure of borosilicate glass, quartz, and thin Teflon films to mixtures of gaseous HNO? and water vapor leads to the subsequent uptake of much larger amounts of water than occurs on the corresponding unexposed surfaces. Infrared spectra show evidence for the formation of nitric acid?water complexes on the surface that leads to this enhanced water uptake. On borosilicate glass, exposure to the nitric acid?water vapor mixture results in surface segregation of the trace metal oxides and their nitrates formed from reaction with HNO?. The majority of these oxides can be removed by rinsing with water; however, smaller, segregated regions of ZnO remain on the surface. The implications for heterogeneous reactions in thin films on surfaces in laboratory systems and in the atmosphere are discussed.

  10. Stress corrosion cracking of zirconium in nitric acid

    SciTech Connect

    Beavers, J A; Griess, J C; Boyd, W K

    1980-01-01

    The susceptibility of zirconium and its common alloys to stress corrosion cracking (SCC) in nitric acid was investigated by slow strain-rate and constant deflection techniques. Cracking occurred at 25/sup 0/C over a wide range of acid concentrations and electrochemical potentials. The crack velocity increased slightly with increasing temperature. The failure mode was transgranular and the morphology was similar to SCC failures of zirconium alloys in other environments. The fracture was very orientation-dependent suggesting that it occurs on a single crystallographic plane in the material. The results of the study are not consistent with a hydrogen mechanism for cracking.

  11. Real-time and indicator-free detection of aqueous nitric oxide with hydrogel film

    NASA Astrophysics Data System (ADS)

    Chao, Yu-Chiang; Yeh, Shih-De; Zan, Hsiao-Wen; Chang, Gao-Fong; Meng, Hsin-Fei; Hung, Chen-Hsiung; Meng, Tzu-Ching; Hsu, Chain-Shu; Horng, Sheng-Fu

    2010-05-01

    A sensing hydrogel film is demonstrated for real-time and indicator-free detection of nitric oxide (NO) in aqueous solution. The film composed of NO probe 11,16-bisphenyl-6,6,21,21-tetramethyl-m-benzi-6,21-porphodimetheno-chloro-zinc(II) and host polymer poly(2-hydroxyethyl methacrylate). The water-containing nature of this sensing hydrogel film makes the surface area high. The response time is bellow 10 s. This sensing hydrogel film also shows high selectivity, sensitivity, and stability in various pH values.

  12. Alternative to Nitric Acid for Passivation of Stainless Steel Alloys

    NASA Technical Reports Server (NTRS)

    Lewis, Pattie L.; Kolody, Mark; Curran, Jerry

    2013-01-01

    Corrosion is an extensive problem that affects the Department of Defense (DoD) and National Aeronautics and Space Administration (NASA). The deleterious effects of corrosion result in steep costs, asset downtime affecting mission readiness, and safety risks to personnel. Consequently, it is vital to reduce corrosion costs and risks in a sustainable manner. The DoD and NASA have numerous structures and equipment that are fabricated from stainless steel. The standard practice for protection of stainless steel is a process called passivation. Typical passivation procedures call for the use of nitric acid; however, there are a number of environmental, worker safety, and operational issues associated with its use. Citric acid offers a variety of benefits including increased safety for personnel, reduced environmental impact, and reduced operational cost. DoD and NASA agreed to collaborate to validate citric acid as an acceptable passivating agent for stainless steel. This paper details our investigation of prior work developing the citric acid passivation process, development of the test plan, optimization of the process for specific stainless steel alloys, ongoing and planned testing to elucidate the process' resistance to corrosion in comparison to nitric acid, and preliminary results.

  13. Reduction Rates for Higher Americium Oxidation States in Nitric Acid

    SciTech Connect

    Grimes, Travis Shane; Mincher, Bruce Jay; Schmitt, Nicholas C

    2015-09-30

    The stability of hexavalent americium was measured using multiple americium concentrations and nitric acid concentrations after contact with the strong oxidant sodium bismuthate. Contrary to our hypotheses Am(VI) was not reduced faster at higher americium concentrations, and the reduction was only zero-order at short time scales. Attempts to model the reduction kinetics using zero order kinetic models showed Am(VI) reduction in nitric acid is more complex than the autoreduction processes reported by others in perchloric acid. The classical zero-order reduction of Am(VI) was found here only for short times on the order of a few hours. We did show that the rate of Am(V) production was less than the rate of Am(VI) reduction, indicating that some Am(VI) undergoes two electron-reduction to Am(IV). We also monitored the Am(VI) reduction in contact with the organic diluent dodecane. A direct comparison of these results with those in the absence of the organic diluent showed the reduction rates for Am(VI) were not statistically different for both systems. Additional americium oxidations conducted in the presence of Ce(IV)/Ce(III) ions showed that Am(VI) is reduced without the typical growth of Am(V) observed in the systems sans Ce ion. This was an interesting result which suggests a potential new reduction/oxidation pathway for Am in the presence of Ce; however, these results were very preliminary, and will require additional experiments to understand the mechanism by which this occurs. Overall, these studies have shown that hexavalent americium is fundamentally stable enough in nitric acid to run a separations process. However, the complicated nature of the reduction pathways based on the system components is far from being rigorously understood.

  14. Experimental study on thermal hazard of tributyl phosphate-nitric acid mixtures using micro calorimeter technique.

    PubMed

    Sun, Qi; Jiang, Lin; Gong, Liang; Sun, Jin-Hua

    2016-08-15

    During PUREX spent nuclear fuel reprocessing, mixture of tributyl phosphate (TBP) and hydrocarbon solvent are employed as organic solvent to extract uranium in consideration of radiation contaminated safety and resource recycling, meanwhile nitric acid is utilized to dissolve the spent fuel into small pieces. However, once TBP contacts with nitric acid or nitrates above 130°C, a heavy "red oil" layer would occur accompanied by thermal runaway reactions, even caused several nuclear safety accident. Considering nitric acid volatility and weak exothermic detection, C80micro calorimeter technique was used in this study to investigate thermal decomposition of TBP mixed with nitric acid. Results show that the concentration of nitric acid greatly influences thermal hazard of the system by direct reactions. Even with a low heating rate, if the concentration of nitric acid increases due to evaporation of water or improper operations, thermal runaway in the closed system could start at a low temperature. PMID:27136728

  15. Biological reduction of nitric oxide in aqueous Fe(II)EDTA solutions.

    PubMed

    van der Maas, Peter; van de Sandt, Thomas; Klapwijk, Bram; Lens, Piet

    2003-01-01

    The reduction of nitric oxide (NO) in aqueous solutions of Fe(II)EDTA is one of the core processes in BioDeNOx, an integrated physicochemical and biological technique for NO(x)() removal from industrial flue gases. NO reduction in aqueous solutions of Fe(II)EDTA (20-25 mM, pH 7.2 +/- 0.2) was investigated in batch experiments at 55 degrees C. Reduction of NO to N(2) was found to be biologically catalyzed with nitrous oxide (N(2)O) as an intermediate. Various sludges from full-scale denitrifying and anaerobic reactors were capable to catalyze NO reduction under thermophilic conditions. The NO reduction rate was not affected by the presence of ethanol or acetate. EDTA-chelated Fe(II) was found to be a suitable electron donor for the biological reduction of nitric oxide to N(2), with the concomitant formation of Fe(III)EDTA. In the presence of ethanol, EDTA-chelated Fe(III) was reduced to Fe(II)EDTA. This study strongly indicates that redox cycling of FeEDTA plays an important role in the biological denitrification process within the BioDeNOx concept. PMID:12892497

  16. Monohydroxamic acids and bridging dihydroxamic acids as chelators to ruthenium(III) and as nitric oxide donors: syntheses, speciation studies and nitric oxide releasing investigations.

    PubMed

    Griffith, Darren; Krot, Krystyna; Comiskey, Jedd; Nolan, Kevin B; Marmion, Celine J

    2008-01-01

    The synthesis and spectroscopic characterisation of novel mononuclear Ru(III)(edta)(hydroxamato) complexes of general formula [Ru(H2edta)(monoha)] (where monoha = 3- or 4-NH2, 2-, 3- or 4-C1 and 3-Me-phenylhydroxamato), as well as the first example of a Ru(III)-N-aryl aromatic hydroxamate, [Ru(H2edta)(N-Me-bha)].H2O (N-Me-bha = N-methylbenzohydroxamato) are reported. Three dinuclear Ru(III) complexes with bridging dihydroxamato ligands of general formula [{Ru(H2edta)}2(mu-diha)] where diha = 2,6-pyridinedihydroxamato and 1,3- or 1,4-benzodihydroxamato, the first of their kind with Ru(III), are also described. The speciation of all of these systems (with the exception of the Ru-1,4-benzodihydroxamic acid and Ru-N-methylbenzohydroxamic systems) in aqueous solution was investigated. We previously proposed that nitrosyl abstraction from hydroxamic acids by Ru(III) involves initial formation of Ru(III)-hydroxamates. Yet, until now, no data on the rate of nitric oxide (NO) release from hydroxamic acids has been published. We now describe a UV-VIS spectroscopic study, where we monitored the decrease in the ligand-to-metal charge-transfer band of a series of Ru(III)-monohydroxamates with time, with a view to gaining an insight into the NO-releasing properties of hydroxamic acids. PMID:18399240

  17. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    SciTech Connect

    Pierce, R. A.

    2012-03-12

    HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into the H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 °C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. At 25 °C, for 6 M HNO{sub 3}, 11 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2.5 g/L and 0.8 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}. The solubility of Gd in 4 M HNO{sub 3} with 0.15 M oxalate at 10 °C is about 1.5 g/L. For 6 M HNO{sub 3} with 0.15 M oxalate, the solubility of Gd at 10

  18. Nitric Acid Dehydration Using Perfluoro Carboxylate and Mixed Sulfonate/Carboxylate Membranes

    SciTech Connect

    R.L. Ames

    2004-09-01

    Perfluoro ionomer membranes are tetrafluoro ethylene-based materials with microheterogeneous structures consisting of a hydrophobic polymer backbone and a hydrophilic side-chain cluster region. Due to the ionomer cluster morphology, these films exhibit unique transport properties. Recent investigations with perfluoro sulfonate and perfluoro sulfonate/carboxylate composite polymers have demonstrated their value in the dehydration of nitric acid and they show potential as an alternative to conventional, energy intensive unit operations in the concentration of acid feeds. As a result, investigations were conducted to determine the feasibility of using pure perfluoro carboxylate and mixed perfluoro sulfonate/carboxylate films for the dehydration of nitric acid because of the speculation of improved water selectivity of the carboxylate pendant chain. During the first phase of these investigations the effort was focused on generating a thin, solution cast perfluoro carboxylate ionomer film, to evaluate the general, chemical and physical characteristics of the polymer, and to assess the material's aqueous transport performance (flux and nitrate separation efficiencies) in pervaporation and high-pressure environments. Results demonstrated that generating robust solution-cast films was difficult yet a number of membranes survived high trans-membrane pressures up to 700 psig. General characterization of the solution cast product showed reduced ion exchange capacities when compared with thicker, ''as received'' perfluoro carboxylate and similar sulfonate films. Small angle x-ray scattering analysis results suggested that the solution cast carboxylate films contained a small fraction of sulfonate terminated side-chains. Aqueous transport experimentation showed that permeate fluxes for both pure water and nitric acid were approximately two orders of magnitude smaller for the carboxylate solution cast membranes when compared to their sulfonate counterparts of similar thickness

  19. Use of extractive distillation to produce concentrated nitric acid

    SciTech Connect

    Campbell, P.C.; Griffin, T.P.; Irwin, C.F.

    1981-04-01

    Concentrated nitric acid (> 95 wt %) is needed for the treatment of off-gases from a fuels-reprocessing plant. The production of concentrated nitric acid by means of extractive distillation in the two-pot apparatus was studied to determine the steady-state behavior of the system. Four parameters, EDP volume (V/sub EDP/) and temperature (T/sub EDP/), acid feed rate, and solvent recycle, were independently varied. The major response factors were percent recovery (CPRR) and product purity (CCP). Stage efficiencies also provided information about the system response. Correlations developed for the response parameters are: CPRR = 0.02(V/sub EDP/ - 800 cc) + 53.5; CCP = -0.87 (T/sub EDP/ - 140/sup 0/C) + 81; eta/sub V,EDP/ = 9.1(F/sub feed/ - 11.5 cc/min) - 0.047(V/sub EDP/ - 800 cc) - 2.8(F/sub Mg(NO/sub 3/)/sub 2// - 50 cc/min) + 390; and eta/sub L,EDP/ = 1.9(T/sub EDP/ - 140/sup 0/C) + 79. A computer simulation of the process capable of predicting steady-state conditions was developed, but it requires further work.

  20. Safety in the Chemical Laboratory: Nitric Acid, Nitrates, and Nitro Compounds.

    ERIC Educational Resources Information Center

    Bretherick, Leslie

    1989-01-01

    Discussed are the potential hazards associated with nitric acid, inorganic and organic nitrate salts, alkyl nitrates, acyl nitrates, aliphatic nitro compounds, aromatic nitro compounds, and nitration reactions. (CW)

  1. Hydrothermal nitric acid treatment for effectual lipid extraction from wet microalgae biomass.

    PubMed

    Lee, Ilgyu; Park, Ji-Yeon; Choi, Sun-A; Oh, You-Kwan; Han, Jong-In

    2014-11-01

    Hydrothermal acid (combined with autoclaving and nitric acid) pretreatment was applied to Nannochloropsis salina as a cost-effective yet efficient way of lipid extraction from wet biomass. The optimal conditions for this pretreatment were determined using a statistical approach, and the roles of nitric acid were also determined. The maximum lipid yield (predicted: 24.6%; experimental: 24.4%) was obtained using 0.57% nitric acid at 120°C for 30min through response surface methodology. A relatively lower lipid yield (18.4%) was obtained using 2% nitric acid; however, chlorophyll and unsaturated fatty acids, both of which adversely affect the refinery and oxidative stability of biodiesel, were found to be not co-extracted. Considering its comparable extractability even from wet biomass and ability to reduce chlorophyll and unsaturated fatty acids, the hydrothermal nitric acid pretreatment can serve as one direct and promising route of extracting microalgae oil. PMID:25255190

  2. Nitrosation and Nitration of Fulvic Acid, Peat and Coal with Nitric Acid

    PubMed Central

    Thorn, Kevin A.; Cox, Larry G.

    2016-01-01

    Nitrohumic acids, produced from base extraction of coals and peats oxidized with nitric acid, have received considerable attention as soil ammendments in agriculture. The nitration chemistry however is incompletely understood. Moreover, there is a need to understand the reaction of nitric acid with natural organic matter (NOM) in general, in the context of a variety of environmental and biogeochemical processes. Suwannee River NOM, Suwannee River fulvic acid, and Pahokee Peat fulvic acid were treated with 15N-labeled nitric acid at concentrations ranging from 15% to 22% and analyzed by liquid and solid state 15N NMR spectroscopy. Bulk Pahokee peat and Illinois #6 coal were also treated with nitric acid, at 29% and 40% respectively, and analyzed by solid state 15N NMR spectroscopy. In addition to nitro groups from nitration of aromatic carbon, the 15N NMR spectra of all five samples exhibited peaks attributable to nitrosation reactions. These include nitrosophenol peaks in the peat fulvic acid and Suwannee River samples, from nitrosation of phenolic rings, and N-nitroso groups in the peat samples, from nitrosation of secondary amides or amines, the latter consistent with the peat samples having the highest naturally abundant nitrogen contents. Peaks attributable to Beckmann and secondary reactions of the initially formed oximes were present in all spectra, including primary amide, secondary amide, lactam, and nitrile nitrogens. The degree of secondary reaction product formation resulting from nitrosation reactions appeared to correlate inversely with the 13C aromaticities of the samples. The nitrosation reactions are most plausibly effected by nitrous acid formed from the reduction of nitric acid by oxidizable substrates in the NOM and coal samples. PMID:27175784

  3. Nitrosation and Nitration of Fulvic Acid, Peat and Coal with Nitric Acid.

    PubMed

    Thorn, Kevin A; Cox, Larry G

    2016-01-01

    Nitrohumic acids, produced from base extraction of coals and peats oxidized with nitric acid, have received considerable attention as soil ammendments in agriculture. The nitration chemistry however is incompletely understood. Moreover, there is a need to understand the reaction of nitric acid with natural organic matter (NOM) in general, in the context of a variety of environmental and biogeochemical processes. Suwannee River NOM, Suwannee River fulvic acid, and Pahokee Peat fulvic acid were treated with 15N-labeled nitric acid at concentrations ranging from 15% to 22% and analyzed by liquid and solid state 15N NMR spectroscopy. Bulk Pahokee peat and Illinois #6 coal were also treated with nitric acid, at 29% and 40% respectively, and analyzed by solid state 15N NMR spectroscopy. In addition to nitro groups from nitration of aromatic carbon, the 15N NMR spectra of all five samples exhibited peaks attributable to nitrosation reactions. These include nitrosophenol peaks in the peat fulvic acid and Suwannee River samples, from nitrosation of phenolic rings, and N-nitroso groups in the peat samples, from nitrosation of secondary amides or amines, the latter consistent with the peat samples having the highest naturally abundant nitrogen contents. Peaks attributable to Beckmann and secondary reactions of the initially formed oximes were present in all spectra, including primary amide, secondary amide, lactam, and nitrile nitrogens. The degree of secondary reaction product formation resulting from nitrosation reactions appeared to correlate inversely with the 13C aromaticities of the samples. The nitrosation reactions are most plausibly effected by nitrous acid formed from the reduction of nitric acid by oxidizable substrates in the NOM and coal samples. PMID:27175784

  4. Nitrosation and nitration of fulvic acid, peat and coal with nitric acid

    USGS Publications Warehouse

    Thorn, Kevin A.; Cox, Larry G.

    2016-01-01

    Nitrohumic acids, produced from base extraction of coals and peats oxidized with nitric acid, have received considerable attention as soil ammendments in agriculture. The nitration chemistry however is incompletely understood. Moreover, there is a need to understand the reaction of nitric acid with natural organic matter (NOM) in general, in the context of a variety of environmental and biogeochemical processes. Suwannee River NOM, Suwannee River fulvic acid, and Pahokee Peat fulvic acid were treated with 15N-labeled nitric acid at concentrations ranging from 15% to 22% and analyzed by liquid and solid state 15N NMR spectroscopy. Bulk Pahokee peat and Illinois #6 coal were also treated with nitric acid, at 29% and 40% respectively, and analyzed by solid state 15N NMR spectroscopy. In addition to nitro groups from nitration of aromatic carbon, the 15N NMR spectra of all five samples exhibited peaks attributable to nitrosation reactions. These include nitrosophenol peaks in the peat fulvic acid and Suwannee River samples, from nitrosation of phenolic rings, and N-nitroso groups in the peat samples, from nitrosation of secondary amides or amines, the latter consistent with the peat samples having the highest naturally abundant nitrogen contents. Peaks attributable to Beckmann and secondary reactions of the initially formed oximes were present in all spectra, including primary amide, secondary amide, lactam, and nitrile nitrogens. The degree of secondary reaction product formation resulting from nitrosation reactions appeared to correlate inversely with the 13C aromaticities of the samples. The nitrosation reactions are most plausibly effected by nitrous acid formed from the reduction of nitric acid by oxidizable substrates in the NOM and coal samples.

  5. Conductance Studies of Aqueous Succinic Acid

    NASA Astrophysics Data System (ADS)

    Apelblat, Alexander; Barthel, Josef

    1992-03-01

    Conductance measurements of aqueous solutions of succinic acid and of di-sodium succinate were performed from 278.15 to 308.15 K and the limiting conductances λ0 (1/2 Succ2- ) are reported. The Waiden product is independent of temperature: λ0(1/2 Succ2-)*η(T) = 0.503 ± 0.001. The salt conductances closely obey the Onsager limiting law. The evaluation of the equilibrium constants for the primary and secondary steps of dissociation, K1 and K2, and the limiting conductances of the hydrosuccinate ion, λ0(HSucc-), are discussed using the Quint and Viallard conductance equation

  6. Liquid-Phase Heat-Release Rates of the Systems Hydrazine-Nitric Acid and Unsymmetrical Dimethylhydrazine-Nitric Acid

    NASA Technical Reports Server (NTRS)

    Somogyi, Dezso; Feiler, Charles E.

    1960-01-01

    The initial rates of heat release produced by the reactions of hydrazine and unsymmetrical dimethylhydrazine with nitric acid were determined in a bomb calorimeter under conditions of forced mixing. Fuel-oxidant weight ratio and injection velocity were varied. The rate of heat release apparently depended on the interfacial area between the propellants. Above a narrow range of injection velocities representing a critical amount of interfacial area, the rates reached a maximum and were almost constant with injection velocity. The maximum rate for hydrazine was about 70 percent greater than that for unsymmetrical dimethylhydrazine. The total heat released did not vary with mixture ratio over the range studied.

  7. Spectroscopic Evidence Against Nitric Acid Trihydrate in Polar Stratospheric Clouds

    NASA Technical Reports Server (NTRS)

    Toon, Owen B.; Tolbert, Margaret A.

    1995-01-01

    Heterogeneous reactions on polar stratospheric clouds (PSC's) play a key role in the photochemical mechanism thought to be responsible for ozone depletion in the Antarctic and Arctic. Reactions of PSC particles activate chlorine to forms that are capable of photochemical ozone destruction, and sequester nitrogen oxides (NOx) that would otherwise deactivate the chlorine. Although the heterogeneous chemistry is now well established, the composition of the clouds themselves is uncertain. It is commonly thought that they are composed of nitric acid trihydrate, although observations have left this question unresolved. Here we reanalyse infrared spectra of type 1 PSCs obtained in Antarctica in September 1987, using recently measured optical constants of the various compounds that might be present in PSCs. We find these PSCs were not composed of nitric acid trihydrate but instead had a more complex compositon, perhaps that of a ternary solution. Because cloud formation is sensitive to their composition, this finding will alter our understanding of the locations and conditions in which PSCs form. In addition, the extent of ozone loss depends on the ability of the PSCs to remove NOx permanently through sedimentation, The sedimentation rates depend on PSC particle size which in turn is controlled by the composition and formation mechanism.

  8. Safe conditions for contacting nitric acid or nitrates with tri-n-butyl phosphate (TBP)

    SciTech Connect

    Hyder, M.L

    1994-01-01

    In response to a request from DOE-SR, the current state of knowledge of the reactions between TBP and aqueous nitrate solutions is critically reviewed, and recommendations are made for the safe operation of SRS separations equipment in which this combination of chemicals may be present. The existing limits for evaporation are validated. Guidelines are presented for cases in which general limits do not apply. The rate of reaction between nitric acid and TBP appears to be controlled by the rate of TBP hydrolysis. The hydrolysis reaction produces dibutyl phosphate and n-butanol. The hydrolysis rate is a strong function of temperature, and becomes very fast at temperatures in the range 130{degrees} to 150{degrees}C. The resulting n-butanol is volatile at high temperatures, boiling at 117.5{degrees}C, but is also subject to exothermic oxidation by nitric acid or nitrates. If oxidation occurs before the n-butanol evaporates, the heat of oxidation may exceed local cooling by convection. The resulting heating will further accelerate the reaction, leading to an energetic runaway and possibly (in confined systems) an explosion. Extensive experiments and practice have shown that in a well-mixed and well-vented aqueous system such as an evaporator, at moderate acidities and temperatures below 130{degrees}C, the heat of reaction is adequately removed by vaporization of steam. In general, the heating will be so slow that natural processes provide adequate cooling at temperatures below 80{degrees}C. Above this temperature, care should be taken to ensure that adequate cooling is available for the amount of TBP that may be present. Experiments suggest that in well-ventilated systems n-butanol evaporation and convective cooling are sufficient to control the reaction at temperatures up to 120{degrees}C.

  9. Degradation of CYANEX 301 in Contact with Nitric Acid Media

    SciTech Connect

    Philippe Marc; Radu Custelcean; Gary S. Groenewold; John R. Klaehn; Dean R. Peterman; Laetitia H. Delmau

    2012-10-01

    The nature of the degradation product obtained upon contacting CYANEX 301 (bis(2,4,4-trimethylpentyl)dithiophosphinic acid) with nitric acid has been elucidated and found to be a disulfide derivative. The first step to the degradation of CYANEX 301 in toluene has been studied using 31P{1H} NMR after being contacted with nitric acid media. The spectrum of the degradation product exhibits a complex multiplet around dP = 80 ppm. A succession of purifications of CYANEX 301 has resulted in single crystals of the acidic form and the corresponding ammonium salt. Unlike the original CYANEX 301, which consists of a complex diastereomeric mixture displaying all possible combinations of chiral orientations at the 2-methyl positions, the purified crystals were shown by single-crystal X-ray diffraction to be racemates, containing 50:50 mixtures of the [R;R] and [S;S] diastereomers. The comparison between the 31P {1H} NMR spectra of the degradation products resulting from the diastereomerically pure CYANEX 301 and the original diastereomeric mixture has elucidated the influence of the isomeric composition on the multiplicity of the 31P {1H} NMR peak. These NMR data indicate the initial degradation leads to a disulfide-bridged condensation product displaying multiple resonances due to phosphorus–phosphorus coupling, which is caused by the inequivalence of the two P atoms as a result of their different chirality. A total of nine different NMR resonances, six of which display phosphorus–phosphorus coupling, could be assigned, and the identity of the peaks corresponding to phosphorus atoms coupled to each other was confirmed by 31P {1H} homodecoupled NMR analysis.

  10. A method for concentrating organic dyes: colorimetric measurements of nitric oxides and sialic acids.

    PubMed

    Lalezari, Parviz; Lekhraj, Rukmani; Casper, Diana

    2011-09-01

    A new method for extraction and concentration of organic dyes that uses a reagent composed of a nonionic detergent mixed with an alcohol is described. We have observed that water-soluble organic dyes are also soluble in nonionic detergents and can be extracted by adding salt, which separates the dye-detergent component from the aqueous phase. We have also found that mixing nonionic detergents with alcohols markedly reduces their viscosity and produces stable, free-flowing, and effective reagents for color extraction. On the basis of these observations, we used a mixture of Triton X-100 and 1-butanol and observed that water-soluble natural and synthetic chromophores, as well as dyes generated in biochemical reactions, can be extracted, concentrated, and analyzed spectrophotometrically. Trypan blue and phenol red are used as examples of synthetic dyes, and red wine is used as an example of phenolic plant pigments. Applications for quantification of nitric oxides and sialic acids are described in more detail and show that as little as 0.15 nmol of nitric oxide and 0.20 nmol of sialic acid can be detected. A major advantage of this method is its ability to concentrate chromophores from dye-containing solutions that otherwise cannot be measured because of their low concentrations. PMID:21605540

  11. Effect of metal ions in a heated nitric acid solution on the corrosion behavior of a titanium-5% tantalum alloy in the hot nitric acid condensate

    NASA Astrophysics Data System (ADS)

    Sano, Y.; Takeuchi, M.; Nakajima, Y.; Hirano, H.; Uchiyama, G.; Nojima, Y.; Fujine, S.; Matsumoto, S.

    2013-01-01

    For evaluating the application of titanium and its alloys as components of equipment for storing nitric acid condensate in spent nuclear fuel reprocessing plants, the corrosion behavior of titanium-5% tantalum alloy (Ti-5Ta) in a continuously renewed hot nitric acid condensate, and particularly the effect of metal ions in the heated nitric acid solution, was investigated. Corrosion experiments in an apparatus designed to renew the condensate at regular intervals showed that the corrosion rate of Ti-5Ta in the condensate increased linearly with the nitric acid concentration. The surface morphology of Ti-5Ta coupons after the corrosion experiments indicated uniform corrosion under any condition. The oxide film on the coupons had nearly constant thickness, and it was composed of mainly lower Ti oxides, such as TiO and Ti2O3, regardless of the nitric acid concentration in the condensate. The experimental results also showed that the addition of metal ions into the heated nitric acid solution increased the nitric acid concentration in the condensate, which resulted in a higher corrosion rate of Ti-5Ta. The corrosion rate increased noticeably as the valence of the metal ion increased and its ionic radius decreased. This effect of metal ions in the heated nitric acid solution on the corrosion rate of Ti-5Ta in the condensate was evaluated quantitatively based on the Gibbs free energy of hydration of the metal ions, and the calculated corrosion rates of Ti-5Ta in the condensate were found to be in good agreement with the experimental values.

  12. Kinetics of the reaction between Pu(III) and Fe(III) in nitric acid solution

    SciTech Connect

    Koltunov, V.S.; Zhuravleva, G.I.

    1988-01-01

    The kinetics of the reaction between Pu/sup (III)/ and Fe/sup (III)/ in an aqueous nitric acid solution in the presence of persulfate ions at a constant ionic strength of the solution was studied spectrophotometrically. It was shown that the reaction is first order with respect to the reagents; its rate is practically independent of the concentration of the H/sup +/ and S/sub 2/O/sub 8//sup 2 -/ ions and with increase in the analytical HNO/sub 3/ concentration at variable ionic strength, it first increases, and then decreases. The temperature dependence of the reaction was determined, and its thermodynamic activation parameters were calculated. A possible mechanism for the reaction between Pu/sup (III)/ and Fe/sup (III)/ was proposed.

  13. Transportation impact analysis for the shipment of low specific activity nitric acid. Revisison 1

    SciTech Connect

    Green, J.R.

    1995-05-16

    This is in support of the Plutonium-Uranium Extraction (PUREX) Facility Low Specific Activity (LSA) Nitric Acid Shipment Environmental Assessment. It analyzes potential toxicological and radiological risks associated with transportation of PUREX Facility LSA Nitric Acid from the Hanford Site to Portsmouth VA, Baltimore MD, and Port Elizabeth NJ.

  14. Evaluation of the Reactivity of Reillex HPQ in 64 Percent Nitric Acid

    SciTech Connect

    Crooks, W.J. III

    2001-02-20

    The purpose of this work was to evaluate the reactivity of Reillex HPQ in 64 percent nitric acid and to address an accident scenario in which 64 percent nitric acid solution is inadvertently added to an HB-Line ion exchange column containing Reillex HPQ anion exchange resin.

  15. 46 CFR 151.50-80 - Nitric acid (70% or less).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Nitric acid (70% or less). 151.50-80 Section 151.50-80 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-80 Nitric acid (70% or less). (a) Tanks, cargo piping,...

  16. 46 CFR 151.50-80 - Nitric acid (70% or less).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Nitric acid (70% or less). 151.50-80 Section 151.50-80 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-80 Nitric acid (70% or less). (a) Tanks, cargo piping,...

  17. Analysis of Steam Heating of a Two-Layer TBP/N-Paraffin/Nitric Acid Mixtures

    SciTech Connect

    Laurinat, J.E.; Hassan, N.M.; Rudisill, T.S.; Askew, N.M.

    1998-07-22

    This report presents an analysis of steam heating of a two-layer tri-n-butyl phosphate (TBP)/n-paraffin-nitric acid mixture.The purpose of this study is to determine if the degree of mixing provided by the steam jet or by bubbles generated by the TBP/nitric acid reaction is sufficient to prevent a runaway reaction.

  18. Kinetics of the reaction of hydroxyl radicals with nitric acid

    NASA Technical Reports Server (NTRS)

    Margitan, J. J.; Watson, R. T.

    1982-01-01

    An extensive study was made of the reaction of hydroxyl radicals with nitric acid in a laser photolysis-resonance fluorescence system. A 266 nm laser was used to photolyze HNO3 in the temperature range 225-415 K at pressures of 20-300 torr. A temperature dependence was detected below room temperature, with a leveling off at 298 K and a wide spread in the rate constants. A pressure dependence was observed over the entire range and was more pronounced at lower temperatures. The results are noted to be in agreement with those of previous investigations. However, the wide range of rate constants are suggested to be a problem for stratospheric HO(x) modeling for anthropogenic effects. No explanation could be given of the varying results obtained by other investigators regarding the kinetics of the reactions.

  19. Two-color vibrationally mediated photodissociation of nitric acid

    SciTech Connect

    Sinha, A.; Vander Wal, R.L.; Butler, L.J.; Crim, F.F.

    1987-08-27

    Two-color vibrationally mediated photodissociation, in which one photon excites an overtone vibration and a second photon of a different wavelength dissociates the highly vibrationally excited molecule prepared by the first photon, is a means of investigating the role of vibrational excitation in photodissociation and of obtaining vibrational overtone excitation spectra. Application of this scheme to nitric acid (HONO/sub 2/) involves exciting the third OH stretching overtone vibration (4v/sub OH/), photodissociating the vibrationally excited molecule with 355-nm light, and detecting the OH fragment using laser-induced fluorescence. These measurements show that most of the OH products are vibrationally unexcited and that about a quarter of the available energy goes into relative translation. The vibrational overtone excitation spectrum has congested P-, Q-, and R-branch rotational structure that forms a 50-cm/sup -1/-wide band.

  20. Acidities of Water and Methanol in Aqueous Solution and DMSO

    ERIC Educational Resources Information Center

    Gao, Daqing

    2009-01-01

    The relative acidities of water and methanol have been a nagging issue. In gas phase, methanol is more acidic than water by 36.0 kJ/mol; however, in aqueous solution, the acidities of methanol and water are almost identical. The acidity of an acid in solution is determined by both the intrinsic gas-phase ionization Gibbs energy and the solvent…

  1. Kinetics of hydrolysis of PET powder in nitric acid by a modified shrinking-core model

    SciTech Connect

    Yoshioka, Toshiaki; Okayama, Nobuchika; Okuwaki, Akitsugu

    1998-02-01

    Poly(ethylene terephthalate) (PET) powder from waste bottles was degraded at atmospheric pressure in 7--13 M nitric acid at 70--100 C for 72 h, to clarify the mechanism of a feed stock recycling process. Terephthalic acid (TPA) and ethylene glycol (EG) were produced by the acid-catalyzed heterogeneous hydrolysis of PET in nitric acid, and the resulting EG was simultaneously oxidized to oxalic acid. The kinetics of the hydrolysis of PET in nitric acid could be explained by a modified shrinking core model of chemical reaction control, in which the effective surface area is proportional to the degree of unreacted PET, affected by the deposition of the product TPA. The apparent rate constant was inversely proportional to particle size and to the concentration of the nitric acid. The activation energy of the reaction was 101.3 kJ/mol.

  2. Buffer capacities of podzolic and peat gleyic podzolic soils to sulfuric and nitric acids

    NASA Astrophysics Data System (ADS)

    Kuznetsov, N. B.; Alekseeva, S. A.; Shashkova, G. V.; Dronova, T. Ya.; Sokolova, T. A.

    2007-04-01

    Soil samples from the main genetic horizons of pale podzolic and peat gleyic podzolic soils from the Central Forest Reserve were subjected to a continuous potentiometric titration by sulfuric and nitric acids. The sulfate sorption capacity was determined in soil mineral horizons. The buffer capacity of mineral horizons of both soils to sulfuric acid was found to be higher than that to the nitric acid. This is explained by the sorption of sulfates via the mechanism of ligand exchange with the release of hydroxyl groups from the surfaces of Fe and Al hydroxide particles and edge faces of clay crystallites. The buffer capacity of organic horizons of the pale podzolic soil to sulfuric acid proved to be higher than that to nitric acid; in organic horizons of the peat gleyic podzolic soil, the buffer capacity to sulfuric acid was lower than that to nitric acid. The reasons for this phenomenon have yet to be investigated.

  3. Toluene nitration in irradiated nitric acid and nitrite solution

    SciTech Connect

    Gracy Elias; Bruce J. Mincher; Stephen P. Mezyk; Jim Muller; Leigh R. Martin

    2011-04-01

    The kinetics, mechanisms, and stable products produced for the aryl alkyl mild ortho-para director - toluene, in irradiated nitric acid and neutral nitrite solutions were investigated using ?, and pulse radiolysis. Electron pulse radiolysis was used to determine the bimolecular rate constants for the reaction of toluene with different transient species produced by irradiation. HPLC with UV detection was primarily used to assess the stable reaction products. GC-MS and LC-MS were used to confirm the results from HPLC. Free-radical nitration reaction products were found in irradiated acidic and neutral media. In acidic medium, the ring substitution and side chain substitution and oxidation produced different nitro products. In ring substitution, nitrogen oxide radicals were added mainly to hydroxyl radical-produced cyclohexadienyl radical, and in side chain substitution they were added to the carbon-centered benzyl radical produced by H-atom abstraction. In neutral nitrite toluene solution, radiolytic ring nitration products approached a statistically random distribution, suggesting a free-radical reaction involving addition of the •NO2 radical.

  4. PROCESS FOR RECOVERING URANIUM FROM AQUEOUS PHOSPHORIC ACID LIQUORS

    DOEpatents

    Schmitt, J.M.

    1962-09-01

    A liquid-liquid extraction method is given for recovering uranium values from aqueous solutions. An acidic aqueous solution containing uranium values is contacted with an organic phase comprising an organic diluent and the reaction product of phosphorous pentoxide and a substantially pure dialkylphosphoric acid. The uranium values are transferred to the organic phase even from aqueous solutions containing a high concentration of strong uranium complexing agents such as phosphate ions. (AEC)

  5. An attempt to theoretically predict third-phase formation in the dimethyldibutyltetradecylmalonamide (DMDBTDMA)/dodecane/water/nitric acid extraction system

    SciTech Connect

    LeFrancois, L.; Tondre, C.; Belnet, F.; Noel, D.

    1999-03-01

    The formation of a third phase in solvent extraction (due to splitting of the organic phase into two layers) often occurs when the aqueous phase is highly concentrated in acids. This has been reported with the extraction system dimethyldibutyltetradecylmalonamide (DMDBTDMA)/n-dodecane/water/nitric acid, both in the presence and absence of metal ions. Whereas many experimental efforts have been made to investigate the effects of different parameters on third-phase formation, very few attempts have been made to predict this phenomenon on theoretical grounds. Because the part played by aggregation of the extractant molecules is recognized, the authors propose a new predictive approach based on the use of the Flory-Huggins theory of polymer solutions, which had been successfully applied for the prediction of phase separation phenomena in nonionic surfactant solutions. The authors show that this model can provide an excellent prediction of the demixing curve (in the absence of metal ions) when establishing the relation between the interaction parameter {chi}{sub 12} calculated from this theory and the nitric acid content of the aqueous phase. Apparent values of the solubility parameter {delta}{sub 2} of the diamide extractant at different acid loadings have been calculated, from which the effect of the nature of the diluent can also be very nicely predicted.

  6. Quantum mechanical study of atmospheric nitrogen oxides and nitric acid: Implications on acid rain

    SciTech Connect

    Richardson, M.D.; Davey, C.A.; Evanseck, J.D.

    1996-12-31

    The energetics of the nonhydrated and monohydrated reaction NO2 + OH {r_arrow} HNO3 were studied using computational methods. Energetic and structural data were obtained using high level ab initio calculations (up to MP4 for energetics). The activation energy was calculated to be around 8 kcal/mol for the nonhydrated system, but the presence of a single water molecule completely eliminated the barrier to nitric acid formation. The hydration of this atmospheric reaction significantly stabilizes the transition structure, leading to an activation energy of about -1 kcal/mol for the reaction. This suggests that enthalpically the reactants may spontaneously form nitric acid in the lower atmosphere where water is available for catalysis, resulting in further production of acid rain.

  7. Dissolution of sulfuric acid tetrahydrate at low temperatures and subsequent growth of nitric acid trihydrate

    NASA Astrophysics Data System (ADS)

    Iraci, Laura T.; Fortin, Tara J.; Tolbert, Margaret A.

    1998-04-01

    Crystalline sulfuric acid tetrahydrate (SAT) has been observed to change phase at temperatures below its melting point, in agreement with recent theoretical predictions of deliquescence. Dissolution of SAT was observed in 63% of experiments expected to show a phase change, leading to formation of a ternary HNO3/H2SO4/H2O solution. This solution, which still contained a portion of the original solid SAT, crystallized to form nitric acid trihydrate (NAT). NAT then continued to grow by condensation of additional nitric acid and water at temperatures several degrees above the ice frost point. This process of SAT dissolution followed by NAT crystallization and growth may offer a mechanism for the formation of type Ia polar stratospheric clouds on frozen sulfate aerosols when SNAT>15.

  8. Solvent extraction study of the thorium nitrate, nitric acid, and tributyl phosphate-dodecane system: density and acidity relationships

    SciTech Connect

    Weinberger, A.J.; Marley, J.L.; Costanzo, D.A.

    1980-05-01

    A solvent extraction study to determine equilibrium conditions of thorium nitrate-nitric acid with 30% tributyl phosphate in normal dodecane has been completed. Experimental conditions studied were 30 to 60{sup 0}C, 0.05 to 1.5 M Th(NO{sub 3}){sub 4}, and 0.0 to 3.0 M HNO{sub 3}. The extractant concentration was constant at 30% tributyl phosphate. The equilibrium experiments have produced data which demonstrate that thorium nitrate concentration, free acid, and density are related in equilibrium behavior between the aqueous and organic phases from 30 to 60{sup 0}C in the 30% tributyl phosphate-dodecane solvent extraction system. The concentration interactions apply to both the two- and three-phase regions. A linear correlation was observed for the density (D) of the aqueous or organic phase and the concentration of thorium and free acid. The general form of the equation is D = a(C/sub Th/ + bC/sub H/) + c, where a is the slope, b is the constant, c is the intercept, and C/sub Th/ and C/sub H/ are the molar concentrations of thorium and free acid respectively. The relationship of temperature, thorium nitrate, and free acid makes possible the definitions of the boundaries between the two- and three-phase regions. This dependence, in turn, permits operational control or simulation studies of the system within the two-phase region. The data demonstrate the interactions of the components of the Thorex system and can be used to improve the mathematical description of equilibrium in the SEPHIS-Thorex computer program.

  9. Cytotoxicity and inhibition of nitric oxide in lipopolysaccharide induced mammalian cell lines by aqueous extracts of brown seaweed.

    PubMed

    Jaswir, Irwandi; Monsur, Hammed Ademola; Simsek, Senay; Amid, Azura; Alam, Zahangir; bin Salleh, Mohammad Noor; Tawakalit, Asiyanbi-Hammed; Octavianti, Fitri

    2014-01-01

    Aqueous extracts obtained from five Malaysian brown seaweeds, Sargassum duplicatum, Sargassum binderi, Sargassum fulvellum, Padina australis, and Turbinaria turbinata, were investigated for their abilities to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-induced macrophage RAW 264.7 cell lines as well as to determine their chemical composition. The percentage yield of extracts varied among species, with P. australis having the lowest yield and T. turbinata having the highest yield. The chemical compositions of the extracts showed that the percentage of sulfate ions as well as uronic acid and total sugar content varied significantly. All extracts contained high fucose and inhibited NO secretion in a dose-dependent manner. Extracts of P. australis and T. turbinata dosed at 200 μg/mL were able to inhibit NO secretion by > 75%. Furthermore, cytotoxicity assays revealed that some extracts were moderately toxic, while others were not. Based on these results, brown seaweed of Malaysian origin should be investigated for the production of additional anti-inflammatory compounds. PMID:25007746

  10. Effect of Nitric Acid Concentrations on Synthesis and Stability of Maghemite Nanoparticles Suspension

    PubMed Central

    Yaacob, Iskandar Idris

    2014-01-01

    Maghemite (γ-Fe2O3) nanoparticles have been synthesized using a chemical coprecipitation method at different nitric acid concentrations as an oxidizing agent. Characterization of all samples performed by several techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), alternating gradient magnetometry (AGM), thermogravimetric analysis (TGA), dynamic light scattering (DLS), and zeta potential. The XRD patterns confirmed that the particles were maghemite. The crystallite size of all samples decreases with the increasing concentration of nitric acid. TEM observation showed that the particles have spherical morphology with narrow particle size distribution. The particles showed superparamagnetic behavior with decreased magnetization values at the increasing concentration of nitric acid. TGA measurement showed that the stability temperature decreases with the increasing concentration of nitric acid. DLS measurement showed that the hydrodynamic particle sizes decrease with the increasing concentration of nitric acid. Zeta potential values show a decrease with the increasing concentration of nitric acid. The increasing concentration of nitric acid in synthesis of maghemite nanoparticles produced smaller size particles, lower magnetization, better thermal stability, and more stable maghemite nanoparticles suspension. PMID:24963510

  11. Uptake of nitric acid by sub-micron-sized ice particles

    NASA Astrophysics Data System (ADS)

    Arora, O. P.; Cziczo, D. J.; Morgan, A. M.; Abbatt, J. P. D.; Niedziela, R. F.

    The uptake of gas phase nitric acid by half-micron-diameter ice crystals has been studied at 230 K by measuring the nitrate content of ice particles which have been exposed to 5 × 10-6 torr of nitric acid in a low temperature flow tube. A cold NaOH-coated denuder is used to distinguish gas-phase nitric acid from adsorbed nitric acid. Ice particle diameters were determined by fitting measured aerosol infrared extinction spectra to spectra calculated via Mie theory, and their number density is measured directly with a CN counter. Under conditions in which the surface is saturated and not all the gas-phase nitric acid adsorbs, the measured uptakes are 1.2 × 1014 molecules/cm² where the surface area is the geometric area of the particles. Within experimental uncertainties, this surface coverage is the same as that measured on thin films of ice formed by freezing liquid water. These results are the first quantitative study of the nitric acid uptake capacity of ice particles, and they provide additional support to the suggestion that ice and snow provide a route for the efficient scavenging of nitric acid from the atmosphere.

  12. Effect of nitric acid concentrations on synthesis and stability of maghemite nanoparticles suspension.

    PubMed

    Nurdin, Irwan; Johan, Mohd Rafie; Yaacob, Iskandar Idris; Ang, Bee Chin

    2014-01-01

    Maghemite (γ-Fe2O3) nanoparticles have been synthesized using a chemical coprecipitation method at different nitric acid concentrations as an oxidizing agent. Characterization of all samples performed by several techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), alternating gradient magnetometry (AGM), thermogravimetric analysis (TGA), dynamic light scattering (DLS), and zeta potential. The XRD patterns confirmed that the particles were maghemite. The crystallite size of all samples decreases with the increasing concentration of nitric acid. TEM observation showed that the particles have spherical morphology with narrow particle size distribution. The particles showed superparamagnetic behavior with decreased magnetization values at the increasing concentration of nitric acid. TGA measurement showed that the stability temperature decreases with the increasing concentration of nitric acid. DLS measurement showed that the hydrodynamic particle sizes decrease with the increasing concentration of nitric acid. Zeta potential values show a decrease with the increasing concentration of nitric acid. The increasing concentration of nitric acid in synthesis of maghemite nanoparticles produced smaller size particles, lower magnetization, better thermal stability, and more stable maghemite nanoparticles suspension. PMID:24963510

  13. Uptake of Gas-Phase Nitric Acid by Water-Ice Surfaces

    NASA Astrophysics Data System (ADS)

    Ullerstam, M.; Abbatt, J. P.

    2004-05-01

    Nitric acid is a widespread molecule found in the atmosphere. It is mainly removed from the troposphere by wet or dry deposition. In colder regions such as the upper troposphere and tropopause where cirrus clouds are formed nitric acid can also be scavenged by cirrus ice particles. The uptake of gas-phase nitric acid by water-ice films has been re-examined with a coated-wall flow tube coupled to a chemical-ionization mass spectrometer (CIMS) at 228K. Previous flow tube studies of this system have shown little dependence of the uptake over the partial pressure regime studied. In these studies the initial, short-term uptake has been the focus and the long term uptake has not been quantified. In this experimental setup it was possible to study the uptake of nitric acid at lower partial pressures resulting in a more atmospherically appropriate determination of the adsorption isotherm and the long term uptake has also been addressed. Measurement of the initial uptake coefficient representing a lower limit will also be presented. Finally, possible burial of nitric acid into the bulk of the ice during continuous growth of the ice film has been studied. In the atmosphere ice particles will be subject to cycles of evaporation and condensation which could cause the nitric acid to be encapsulated into the particle, especially since the major part of the adsorption has been proven to be irreversible. This could enhance the ice particles capacity of scavenging nitric acid.

  14. Thermal hazard evaluation of lauroyl peroxide mixed with nitric acid.

    PubMed

    Tsai, Lung-Chang; You, Mei-Li; Ding, Mei-Fang; Shu, Chi-Min

    2012-01-01

    Many thermal runaway incidents have been caused by organic peroxides due to the peroxy group, -O-O-, which is essentially unstable and active. Lauroyl peroxide (LPO) is also sensitive to thermal sources and is incompatible with many materials, such as acids, bases, metals, and ions. From the thermal decomposition reaction of various concentrations of nitric acid (HNO3) (from lower to higher concentrations) with LPO, experimental data were obtained as to its exothermic onset temperature (T0), heat of decomposition (ΔHd), isothermal time to maximum rate (TMRiso), and other safety parameters exclusively for loss prevention of runaway reactions and thermal explosions. As a novel finding, LPO mixed with HNO3 can produce the detonation product of 1-nitrododecane. We used differential scanning calorimetry (DSC), thermal activity monitor III (TAM III), and gas chromatography/mass spectrometer (GC/MS) analyses of the reactivity for LPO and itself mixed with HNO3 to corroborate the decomposition reactions and reaction mechanisms in these investigations. PMID:22763742

  15. Study on reduction and back extraction of Pu(IV) by urea derivatives in nitric acid conditions

    SciTech Connect

    Ye, G.A.; Xiao, S.T.; Yan, T.H.; Lin, R.S.; Zhu, Z.W.

    2013-07-01

    The reduction kinetics of Pu(IV) by hydroxyl-semicarbazide (HSC), hydroxyurea (HU) and di-hydroxyurea (DHU) in nitric acid solutions were investigated separately with adequate kinetic equations. In addition, counter-current cascade experiments were conducted for Pu split from U in nitric acid media using three kinds of reductant, respectively. The results show that urea derivatives as a kind of novel salt-free reductant can reduce Pu(IV) to Pu(III) rapidly in the nitric acid solutions. The stripping experimental results showed that Pu(IV) in the organic phase can be stripped rapidly to the aqueous phase by the urea derivatives, and the separation factors of plutonium /uranium can reach more than 10{sup 4}. This indicates that urea derivatives is a kind of promising salt-free agent for uranium/plutonium separation. In addition, the complexing effect of HSC with Np(IV) was revealed, and Np(IV) can be back-extracted by HSC with a separation factor of about 20.

  16. 40 CFR 418.50 - Applicability; description of the nitric acid subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Applicability; description of the nitric acid subcategory. 418.50 Section 418.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric...

  17. 40 CFR 418.50 - Applicability; description of the nitric acid subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Applicability; description of the nitric acid subcategory. 418.50 Section 418.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric...

  18. 40 CFR 418.50 - Applicability; description of the nitric acid subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 30 2012-07-01 2012-07-01 false Applicability; description of the nitric acid subcategory. 418.50 Section 418.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric...

  19. 40 CFR 418.50 - Applicability; description of the nitric acid subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 29 2011-07-01 2009-07-01 true Applicability; description of the nitric acid subcategory. 418.50 Section 418.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric...

  20. 40 CFR 418.50 - Applicability; description of the nitric acid subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Applicability; description of the nitric acid subcategory. 418.50 Section 418.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric...

  1. SALICYLIC ACID- AND NITRIC OXIDE-MEDIATED SIGNAL TRANSDUCTION IN DISEASE RESISTANCE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current advances in plant defense signaling is discussed, with emphasis on the role of nitric oxide and salicylic acid in the development of disease resistance. Nitric Oxide has recently been shown to have an important role in plant disease resistance. We show an increase in NOS-like activity in TMV...

  2. Assessment of electrochemical potentiokinetic reactivation tests to qualify stainless steel for nitric acid service

    SciTech Connect

    Olsen, A.R.; Dillon, J.J.; Peters, A.H.; Clift, T.L.

    1986-12-31

    To minimize the costs and delivery time delays associated with purchasing type 304L stainless steel materials for service in nitric-acid-containing media, an alternative to the current Oak Ridge Y-12 Plant requirement of testing in accordance with American Society for Testing and Materials (ASTM) A 262, Practice C (the boiling nitric acid test), is being sought. A possible candidate is the electrochemical potentiokinetic reactivation (EPR) test being developed for the nuclear industry and under consideration for acceptance as an ASTM standard. Based on a review of the literature and some limited screening tests, this test, as currently proposed, is not a suitable substitute for the nitric acid test. However, with additional development the EPR test is a likely candidate for providing a quantitative substitute for the current qualitative oxalic acid etching (ASTM A 282, Practice A) often used to accept, but not reject, materials for use in a nitric acid medium.

  3. Interactions of nitric oxide with copper(II) dithiocarbamates in aqueous solution.

    PubMed

    Díaz, Alicia; Ortiz, Mayreli; Sánchez, Ileana; Cao, Roberto; Mederos, Alfredo; Sanchiz, Joaquin; Brito, Felipe

    2003-07-01

    This is the first report on the formation of air-stable copper nitrosyl complexes. The interaction of nitric oxide, NO, with Cu(DTC)(2).3H(2)O (DTC: dithiocarbamate) and was studied in aqueous solution at pH 7.4 and 293 K. The stability constants were determined from UV-Vis data, using LETAGROP program. The high values obtained, log beta(1)=9.743(5) and log beta(2)=15.44(2) for Cu(ProDTC)(2)-NO, (ProDTC=L-prolinedithiocarbamate) and log beta(1)=8.723(5) and log beta(2)=11.45(2) for Cu(MorDTC)(2)-NO system, (MorDTC=morpholyldithiocarbamate), indicate the formation of two stable nitrosyl complexes, Cu(DTC)(2)NO and Cu(DTC)(2)(NO)(2). Coordinated NO is neither affected by the presence of air nor when the solution is purged with Ar. Cu(MorDTC)(2)NO.3H(2)O was isolated in the solid state and its nuNO (IR) band at 1682 cm(-1), but affected by temperature variations over 333 K. PMID:12818798

  4. Analysis of seasonal variation of stratospheric nitric acid

    NASA Astrophysics Data System (ADS)

    Gruzdev, A. N.

    1998-11-01

    Data from the draft COSPAR reference model for stratospheric nitric acid (HNO3) are analysed. Eight months of LIMS HNO3 measurements allow the analysis of dynamics of regimes associated with the annual HNO3 maximum followed by the HNO3 decrease in the Northern Hemisphere and the annual HNO3 minimum followed by the HNO3 increase in the Southern Hemisphere. The HNO3 minimum is noted earlier (in November) in the Southern Hemisphere subtropical upper stratosphere, from where the regime of minimum HNO3 values propagates to the southern high-latitude middle stratosphere, and then (in Austral summer) the equatorward propagation of the regime is observed, with a persistent downward component. The regime of the HNO3 annual maximum in the Northern Hemisphere propagates from the Arctic lower stratosphere (in autumn) and from the tropical middle stratosphere (in late summer), so that in the mid-latitude middle stratosphere the downward propagation of the regime is observed. Evolution of areas with HNO3 increase and decrease by 1 ppbv against the January HNO3 distribution quantifies intensity of the HNO3 decrease in winter-spring in the Northern Hemisphere and the HNO3 increase in Austral summer-autumn in the Southern Hemisphere.

  5. Morphology of nitric acid and water ice films

    NASA Technical Reports Server (NTRS)

    Keyser, Leon F.; Leu, Ming-Taun

    1993-01-01

    Ice films have been used to simulate stratospheric cloud surfaces in order to obtain laboratory data on solubilities and heterogeneous reaction rates. In the present study, environmental scanning electron microscopy (ESEM) is used to study thin films of both water ice and nitric acid ice near the composition of the trihydrate. The ices are formed by vapor deposition onto aluminum or borosilicate-glass substrates cooled to about 200 K. Micrographs are recorded during the deposition process and during subsequent annealing at higher temperatures. The results show that the ice films are composed of loosely consolidated granules, which range from about 1 to 20 microns in size at temperatures between 197 and 235 K. Cubic water ice is sometimes observed at 200 K, which converts to the hexagonal form at slightly higher temperatures. The loose packing of the granules confirms the high porosities of these films obtained from separate bulk porosity measurements. Average surface areas calculated from the observed granule sizes range from about 0.2 to 1 sq m/g and agree with surface areas obtained by gas-adsorption (BET) analysis of annealed ice films. For unannealed films, the BET areas are about an order of magnitude higher than the ESEM results, implying that the unannealed ices contain microporosity which is lost during the annealing process.

  6. Study of inlet materials for sampling atmospheric nitric acid

    SciTech Connect

    Neuman, J.A.; Huey, L.G.; Ryerson, T.B.; Fahey, D.W. |

    1999-04-01

    The adsorption of nitric acid (HNO{sub 3}) from a flowing gas stream is studied for a variety of wall materials to determine their suitability for use in atmospheric sampling instruments. Parts per billion level mixtures of HNO{sub 3} in synthetic air flow through tubes of different materials such that >80% of the molecules interact with the walls. A chemical ionization mass spectrometer with a fast time response and high sensitivity detects HNO{sub 3} that is not adsorbed on the tube walls. Less than 5% of available HNO{sub 3} is adsorbed on Teflon fluoropolymer tubing after 1 min of HNO{sub 3} exposure, whereas >70% is lost on walls made of stainless steel, glass, fused silica, aluminum, nylon, silica-steel, and silane-coated glass. Glass tubes exposed to HNO{sub 3} on the order of hours passivate with HNO{sub 3} adsorption dropping to zero. The adsorption of HNO{sub 3} on PFA Teflon tubing (PFA) is nearly temperature-independent from 10 to 80 C, but below {minus}10 C nearly all HNO{sub 3} that interacts with PFA is reversibly adsorbed. In ambient and synthetic air, humidity increases HNO{sub 3} adsorption. The results suggest that Teflon at temperatures above 10 C is an optimal choice for inlet surfaces used for in situ measurements of HNO{sub 3} in the ambient atmosphere.

  7. Infrared spectrum of nitric acid dihydrate: Influence of particle shape.

    PubMed

    Wagner, Robert; Möhler, Ottmar; Saathoff, Harald; Stetzer, Olaf; Schurath, Ulrich

    2005-03-24

    In situ Fourier transform infrared (FTIR) extinction spectra of airborne alpha-NAD microparticles generated by two different methods were recorded in the large coolable aerosol chamber AIDA of Forschungszentrum Karlsruhe. The extinction spectrum of alpha-NAD crystals obtained by shock freezing of a HNO3/H2O gas mixture could be accurately reproduced using Mie theory with published refractive indices of alpha-NAD as input. In contrast, Mie theory proved to be inadequate to properly reproduce the infrared extinction spectrum of alpha-NAD crystals which were formed via homogeneous nucleation of supercooled HNO3/H2O solution droplets, evaporating slowly on a time scale of several hours at about 195 K. Much better agreement between measured and calculated extinction spectra was obtained by T-matrix calculations assuming oblate particles with aspect ratios greater than five. This indicates that strongly aspherical alpha-NAD crystals are obtained when supercooled nitric acid solution droplets freeze and grow slowly, a process which has been discussed as a potential pathway to the formation of crystalline polar stratospheric cloud (PSC) particles. PMID:16833561

  8. The extraction of actinides from nitric acid solutions with diamides of dipicolinic acid

    NASA Astrophysics Data System (ADS)

    Lapka, Joseph L.; Paulenova, Alena; Alyapyshev, Mikhail Yu; Babain, Vasiliy A.; Law, Jack D.; Herbst, R. Scott

    2010-03-01

    Diamides of dipicolinic acid (N,N'-diethyl-N,N'-ditolyl-dipicolinamide, EtTDPA) were synthesized and evaluated for their extraction capability for actinides. In this work the extractions of neptunium(V), protactinium(V), and thorium(IV) with EtTDPA in a polar fluorinated diluent from nitric acid were investigated. EtTDPA shows a high affinity for Th(IV) even at millimolar concentrations. Np(V) and Pa(V) are both reasonably extractable with EtTDPA; however, near saturated solutions are required to achieve appreciable distribution ratios. A comparison with previously published actinide extraction data is given.

  9. Aqueous-phase source of formic acid in clouds

    NASA Technical Reports Server (NTRS)

    Chameides, W. L.; Davis, D. D.

    1983-01-01

    The coupled gas- and aqueous-phase cloud chemistry of HCOOH were examined for controlling factors in the acidity of cloud and rainwater. Attention was given to the aqueous OH/HO2 system that yields an OH species that is highly reactive with other species, notably SO2 and the formaldehyde/formic acid complex. A numerical model was developed to simulate the cloud chemistry in the remote troposphere, with considerations given to CH4-CO-NO(x)-O3-H(x)O(y) system. It was determined that aqueous phase OH radicals can produce and destroy formic acid droplets in daylight conditions, as well as control formic acid levels in rainwater. It is sugested that the same types of reactions may be involved in the control of acetic acid and other organic acids.

  10. An evaluation of foaming potential in the IDMS melter. [Neutralization of waste sludge base components (hydroxides and carbonates) with nitric acid

    SciTech Connect

    Hutson, N.D.

    1992-10-22

    The present DWPF flowsheet calls for the chemical treatment of waste sludge with 90 wt% formic acid prior to the addition of the Precipitate Hydrolysis Aqueous (PHA) product. An alternative processing methodology, denoted the Nitric Acid Flowsheet'', has been proposed. In the application of this flowsheet, nitric acid would be used to neutralize sludge base components (hydroxides and carbonates) prior to the addition of late wash PHA. The late wash PHA will contain sufficient quantities of formic acid to adequately complete necessary reduction-oxidation (REDOX) reactions. The use of this flowsheet may result in a change in the nominal concentrations of two of the major REDOX reaction participants: formate (HCOO[sup minus]) and nitrate (NO[sub 3][sup minus]).

  11. Nitric oxide and salicylic acid signaling in plant defense

    PubMed Central

    Klessig, Daniel F.; Durner, Jörg; Noad, Robert; Navarre, Duroy A.; Wendehenne, David; Kumar, Dhirendra; Zhou, Jun Ma; Shah, Jyoti; Zhang, Shuqun; Kachroo, Pradeep; Trifa, Youssef; Pontier, Dominique; Lam, Eric; Silva, Herman

    2000-01-01

    Salicylic acid (SA) plays a critical signaling role in the activation of plant defense responses after pathogen attack. We have identified several potential components of the SA signaling pathway, including (i) the H2O2-scavenging enzymes catalase and ascorbate peroxidase, (ii) a high affinity SA-binding protein (SABP2), (iii) a SA-inducible protein kinase (SIPK), (iv) NPR1, an ankyrin repeat-containing protein that exhibits limited homology to IκBα and is required for SA signaling, and (v) members of the TGA/OBF family of bZIP transcription factors. These bZIP factors physically interact with NPR1 and bind the SA-responsive element in promoters of several defense genes, such as the pathogenesis-related 1 gene (PR-1). Recent studies have demonstrated that nitric oxide (NO) is another signal that activates defense responses after pathogen attack. NO has been shown to play a critical role in the activation of innate immune and inflammatory responses in animals. Increases in NO synthase (NOS)-like activity occurred in resistant but not susceptible tobacco after infection with tobacco mosaic virus. Here we demonstrate that this increase in activity participates in PR-1 gene induction. Two signaling molecules, cGMP and cyclic ADP ribose (cADPR), which function downstream of NO in animals, also appear to mediate plant defense gene activation (e.g., PR-1). Additionally, NO may activate PR-1 expression via an NO-dependent, cADPR-independent pathway. Several targets of NO in animals, including guanylate cyclase, aconitase, and mitogen-activated protein kinases (e.g., SIPK), are also modulated by NO in plants. Thus, at least portions of NO signaling pathways appear to be shared between plants and animals. PMID:10922045

  12. Nitric oxide production by visible light irradiation of aqueous solution of nitrosyl ruthenium complexes.

    PubMed

    Sauaia, Marília Gama; de Lima, Renata Galvão; Tedesco, Antonio Claudio; da Silva, Roberto Santana

    2005-12-26

    [Ru(II)L(NH(3))(4)(pz)Ru(II)(bpy)(2)(NO)](PF(6))(5) (L is NH(3), py, or 4-acpy) was prepared with good yields in a straightforward way by mixing an equimolar ratio of cis-[Ru(NO(2))(bpy)(2)(NO)](PF(6))(2), sodium azide (NaN(3)), and trans-[RuL(NH(3))(4)(pz)] (PF(6))(2) in acetone. These binuclear compounds display nu(NO) at ca. 1945 cm(-)(1), indicating that the nitrosyl group exhibits a sufficiently high degree of nitrosonium ion (NO(+)). The electronic spectrum of the [Ru(II)L(NH(3))(4)(pz)Ru(II)(bpy)(2)(NO)](5+) complex in aqueous solution displays the bands in the ultraviolet and visible regions typical of intraligand and metal-to-ligand charge transfers, respectively. Cyclic voltammograms of the binuclear complexes in acetonitrile give evidence of three one-electron redox processes consisting of one oxidation due to the Ru(2+/3+) redox couple and two reductions concerning the nitrosyl ligand. Flash photolysis of the [Ru(II)L(NH(3))(4)(pz)Ru(II)(bpy)(2)(NO)](5+) complex is capable of releasing nitric oxide (NO) upon irradiation at 355 and 532 nm. NO production was detected and quantified by an amperometric technique with a selective electrode (NOmeter). The irradiation at 532 nm leads to NO release as a consequence of a photoinduced electron transfer. All species exhibit similar photochemical behavior, a feature that makes their study extremely important for their future application in the upgrade of photodynamic therapy in living organisms. PMID:16363866

  13. Studies on the oxidation of hexamethylbenzene 1: Oxidation of hexamethylbenzene with nitric acid

    NASA Technical Reports Server (NTRS)

    Chiba, K.; Tomura, S.; Mizuno, T.

    1986-01-01

    The oxidative reaction of hexamethylbenzene (HMB) with nitric acid was studied, and the hitherto unknown polymethylbenzenepolycarboxylic acids were isolated: tetramethylphthalic anhydride, tetramethylisophthalic acid, 1,3,5-, 1,2,4- and 1,2,3-trimethylbenzenetricarboxylic acids. When HMB was warmed with 50% nitric acid at about 80 C, tetramethylphthalic anhydride and tetramethylisophthalic acid were initially produced. The continued reaction led to the production of trimethylbenzenetricarboxylic acids, but only slight amounts of dimethylbenzenetetracarboxylic acids were detected in the reaction mixture. Whereas tetramethylphthalic anydride and tetramethylisophthalic acid were obtained, pentamethylbenzoic acid, a possible precursor of them, was scarcely produced. On the other hand, a yellow material extracted with ether from the initial reaction mixture contained bis-(nitromethyl)prehnitene (CH3)4C6(CH2NO2)2, which was easily converted into the phthalic anhydride.

  14. Proton transfer reactions between nitric acid and acetone, hydroxyacetone, acetaldehyde and benzaldehyde in the solid phase.

    PubMed

    Lasne, Jérôme; Laffon, Carine; Parent, Philippe

    2012-12-01

    The heterogeneous and homogeneous reactions of acetone, hydroxyacetone, acetaldehyde and benzaldehyde with solid nitric acid (HNO(3)) films have been studied with Reflection-Absorption Infrared Spectroscopy (RAIRS) under Ultra-High Vacuum (UHV) conditions in the 90-170 K temperature range. In the bulk or at the surface of the films, nitric acid transfers its proton to the carbonyl function of the organic molecules, producing protonated acetone-H(+), hydroxyacetone-H(+), acetaldehyde-H(+) and benzaldehyde-H(+), and nitrate anions NO(3)(-), a reaction not observed when nitric acid is previously hydrated [J. Lasne, C. Laffon and Ph. Parent, Phys. Chem. Chem. Phys., 2012, 14, 697]. This provides a molecular-scale description of the carbonyl protonation reaction in an acid medium, the first step of the acid-catalyzed condensation of carbonyl compounds, fuelling the growth of secondary organic aerosols (SOA) in the atmosphere. PMID:23090634

  15. Disposition and transportation of surplus radioactive low specific activity nitric acid. Volume 1, Environmental Assessment

    SciTech Connect

    1995-05-01

    DOE is deactivating the PUREX plant at Hanford; this will involve the disposition of about 692,000 liters (183,000 gallons) of surplus nitric acid contaminated with low levels of U and other radionuclides. The nitric acid, designated as low specific activity, is stored in 4 storage tanks at PUREX. Five principal alternatives were evaluated: transfer for reuse (sale to BNF plc), no action, continued storage in Hanford upgraded or new facility, consolidation of DOE surplus acid, and processing the LSA nitric acid as waste. The transfer to BNF plc is the preferred alternative. From the analysis, it is concluded that the proposed disposition and transportation of the acid does not constitute a major federal action significantly affecting the quality of the human environment within the meaning of NEPA; therefore an environmental impact statement is not required.

  16. Nitrones are able to release nitric oxide in aqueous environment under hydroxyl free radical attack.

    PubMed

    Croitoru, Mircea Dumitru; Ibolya, Fülöp; Pop, Maria Cristiana; Dergez, Timea; Mitroi, Brânduşa; Dogaru, Maria Titica; Tokés, Béla

    2011-10-30

    Importance of a nitric oxide donor that can act as a spin trap might bring some new therapeutic possibilities regarding the treatment of ischemic diseases by reducing the intensity of free radical produced reperfusion lesions. These substances might be also used as a new type of photo protectors since they can absorb UV radiation, capture free radicals formed by interaction of UV radiation with tissue constituents, and tanning of the skin will be permitted due to nitric oxide release. The purpose of this work was to measure the ability of nitrones to release nitric oxide and how different factors (temperature, nitrone concentration, and free radicals) influence the releasing ability. Mostly, indirect determination of nitric oxide was carried out, by measuring nitrite and nitrate amounts (as decomposition products of nitric oxide), all nitrones proved to release significant amounts of nitric oxide. Nitrite measurements were made based on an HPLC-VIS method that uses pre-column derivatization of nitrite by forming an azo dye (limit of quantification: 5ng/ml). No good correlation was found between the amount of nitric oxide and temperature for most studied nitrones but between the formation of nitric oxide and nitrone concentration an asymptotic correlation was found. Fenton reagent also yielded formation of nitric oxide from nitrones and formed amounts were not different from those recorded for UV irradiation. Most of the nitrones effectively released about 0.5% of the maximum amount of nitric oxide that is chemically possible and estimated concentrations of 0.1μM were present in the solutions during decomposition. PMID:21645628

  17. Laboratory studies of 2H evaporator scale dissolution in dilute nitric acid

    SciTech Connect

    Oji, L.

    2014-09-23

    The rate of 2H evaporator scale solids dissolution in dilute nitric acid has been experimentally evaluated under laboratory conditions in the SRNL shielded cells. The 2H scale sample used for the dissolution study came from the bottom of the evaporator cone section and the wall section of the evaporator cone. The accumulation rate of aluminum and silicon, assumed to be the two principal elemental constituents of the 2H evaporator scale aluminosilicate mineral, were monitored in solution. Aluminum and silicon concentration changes, with heating time at a constant oven temperature of 90 deg C, were used to ascertain the extent of dissolution of the 2H evaporator scale mineral. The 2H evaporator scale solids, assumed to be composed of mostly aluminosilicate mineral, readily dissolves in 1.5 and 1.25 M dilute nitric acid solutions yielding principal elemental components of aluminum and silicon in solution. The 2H scale dissolution rate constant, based on aluminum accumulation in 1.5 and 1.25 M dilute nitric acid solution are, respectively, 9.21E-04 ± 6.39E-04 min{sup -1} and 1.07E-03 ± 7.51E-05 min{sup -1}. Silicon accumulation rate in solution does track the aluminum accumulation profile during the first few minutes of scale dissolution. It however diverges towards the end of the scale dissolution. This divergence therefore means the aluminum-to-silicon ratio in the first phase of the scale dissolution (non-steady state conditions) is different from the ratio towards the end of the scale dissolution. Possible causes of this change in silicon accumulation in solution as the scale dissolution progresses may include silicon precipitation from solution or the 2H evaporator scale is a heterogeneous mixture of aluminosilicate minerals with several impurities. The average half-life for the decomposition of the 2H evaporator scale mineral in 1.5 M nitric acid is 12.5 hours, while the half-life for the decomposition of the 2H evaporator scale in 1.25 M nitric acid is 10

  18. Spectrofluorimetric determination of nitric oxide at trace levels with 5,6-diamino-1,3-naphthalene disulfonic acid.

    PubMed

    Zhang, Xian; Wang, Hong; Liang, Shu-Cai; Zhang, Hua-Shan

    2002-03-01

    Based on the selective reaction that 5,6-diamino-1,3-naphthalene disulfonic acid (DANDS) traps nitric oxide (NO) in the presence of dioxygen to yield the highly fluorescent form, 1-[H]-naphthotriazole-6,8-disulfonic acid in moderately alkaline medium, a new spectrofluorimetric method for the determination of NO has been reported. The method offered the advantage of specificity, sensitivity and a simple protocol for the direct detection of NO in aqueous solution. The linear calibration range for NO was 0.04-1.44 mumoll(-1) with a 3sigma detection limit of 0.6 nmoll(-1). The proposed method has been used to monitor the release of NO from S-nitrosocysteine, a NO-releasing agent. PMID:18968522

  19. Aqueous infrared carboxylate absorbances: Aliphatic di-acids

    USGS Publications Warehouse

    Cabaniss, S.E.; Leenheer, J.A.; McVey, I.F.

    1998-01-01

    Aqueous attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra of 18 aliphatic di-carboxylic acids are reported as a function of pH. The spectra show isosbestic points and intensity changes which indicate that Beer's law is obeyed, and peak frequencies lie within previously reported ranges for aqueous carboxylates and pure carboxylic acids. Intensity sharing from the symmetric carboxylate stretch is evident in many cases, so that bands which are nominally due to alkyl groups show increased intensity at higher pH. The asymmetric stretch of the HA- species is linearly related to the microscopic acidity constant of the H2A species, with ??pK 2 intervening atoms). The results suggest that aqueous ATR-FTIR may be able to estimate 'intrinsic' pKa values of carboxylic acids, in addition to providing quantitative estimates of ionization. ?? 1998 Elsevier Science B.V. All rights reserved.

  20. Oxidation of nitric oxide in aqueous solution to nitrite but not nitrate: comparison with enzymatically formed nitric oxide from L-arginine.

    PubMed Central

    Ignarro, L J; Fukuto, J M; Griscavage, J M; Rogers, N E; Byrns, R E

    1993-01-01

    Nitric oxide (NO) in oxygen-containing aqueous solution has a short half-life that is often attributed to a rapid oxidation to both NO2- and NO3-. The chemical fate of NO in aqueous solution is often assumed to be the same as that in air, where NO is oxidized to NO2 followed by dimerization to N2O4. Water then reacts with N2O4 to form both NO2- and NO3-. We report here that NO in aqueous solution containing oxygen is oxidized primarily to NO2- with little or no formation of NO3-. In the presence of oxyhemoglobin or oxymyoglobin, however, NO and NO2- were oxidized completely to NO3-. Methemoglobin was inactive in this regard. The unpurified cytosolic fraction from rat cerebellum, which contains constitutive NO synthase activity, catalyzed the conversion of L-arginine primarily to NO3- (NO2-/NO3- ratio = 0.25). After chromatography on DEAE-Sephacel or affinity chromatography using 2',5'-ADP-Sepharose 4B, active fractions containing NO synthase activity catalyzed the conversion of L-arginine primarily to NO2- (NO2-/NO3- ratio = 5.6) or only to NO2-, respectively. Unpurified cytosol from activated rat alveolar macrophages catalyzed the conversion of L-arginine to NO2- without formation of NO3-. Addition of 30 microM oxyhemoglobin to all enzyme reaction mixtures resulted in the formation primarily of NO3- (NO2-/NO3- ratio = 0.09 to 0.20). Cyanide ion, which displaces NO2- from its binding sites on oxyhemoglobin, inhibited the formation of NO3-, thereby allowing NO2- to accumulate. These observations indicate clearly that the primary decomposition product of NO in aerobic aqueous solution is NO2- and that further oxidation to NO3- requires the presence of additional oxidizing species such as oxyhemoproteins. Images Fig. 5 Fig. 6 PMID:7690141

  1. Batch salicylic acid nitration by nitric acid/acetic acid mixture under isothermal, isoperibolic and adiabatic conditions.

    PubMed

    Andreozzi, R; Canterino, M; Caprio, V; Di Somma, I; Sanchirico, R

    2006-12-01

    Runaway phenomena and thermal explosions can originate during the nitration of salicylic acid by means of a nitric acid/acetic acid mixture when the thermal control is lost, mainly as a result of the formation and thermal decomposition of picric acid. The prediction of the behaviour of this system is thus of great importance in view of possible industrial applications and the need to avoid the occurrence of unwanted dangerous events. During a previous investigation a model was developed to simulate its behaviour when the starting concentration of the substrate is too low, thus, preventing the precipitation of poor soluble intermediates. In this work this model is extended to deal with more concentrated systems even in case of a solid phase separating during the process. To this purpose the previously assessed dependence of the solubility of 3-nitro and 5-nitrosalicylic acids upon temperature and nitric acid concentration is included in the model. It is assumed that when 3-nitro and 5-nitrosalicylic acids are partially suspended in the reacting medium a kinetic regime of "dissolution with reaction" is established; that is, the redissolution of these species is a fast process compared to the successive nitration to give dinitroderivatives. Good results are obtained in the comparison of the experimental data with those calculated both in isoperibolic and adiabatic conditions when the revised model is used. PMID:16842908

  2. PROCESS OF SECURING PLUTONIUM IN NITRIC ACID SOLUTIONS IN ITS TRIVALENT OXIDATION STATE

    DOEpatents

    Thomas, J.R.

    1958-08-26

    >Various processes for the recovery of plutonium require that the plutonium be obtalned and maintained in the reduced or trivalent state in solution. Ferrous ions are commonly used as the reducing agent for this purpose, but it is difficult to maintain the plutonium in a reduced state in nitric acid solutions due to the oxidizing effects of the acid. It has been found that the addition of a stabilizing or holding reductant to such solution prevents reoxidation of the plutonium. Sulfamate ions have been found to be ideally suitable as such a stabilizer even in the presence of nitric acid.

  3. Effects of nitric acid on carbachol reactivity of the airways in normal and allergic sheep

    SciTech Connect

    Abraham, W.M.; Kim, C.S.; King, M.M.; Oliver, W. Jr.; Yerger, L.

    1982-01-01

    The airway effects of a 4-hr exposure (via a Plexiglas hood) to 1.6 ppm nitric acid vapor were evaluated in seven normal and seven allergic sheep, i.e., animals that have a history of reacting with bronchospasm to inhalation challenge with Ascaris suum antigen. The nitric acid vapor was generated by ultrasonic nebulization of a 2% nitric acid solution. Airway effects were assessed by measuring the change in specific pulmonary flow resistance before and after a standard inhalation challenge with 2.5% carbachol aerosol. Nitric acid exposure did not produce bronchoconstriction in either group. Pre-exposure increases in specific pulmonary flow resistance after carbachol inhalation were 68% (SD+/- 13%) and 82% (SD+/- 35%) for the normal and allergic sheep, respectively. Within 24 hr, the largest post-exposure increases in specific pulmonary flow resistance for the normal and allergic sheep were 108% (SD+/- 51%(P<.06)) and 175% (SD+/- 87% (p<.02)), respectively. We conclude that a short-term exposure to nitric acid vapor at levels below the industrial threshold limit (2 ppm), produces airway hyperreactivity to aerosolized carbachol in allergic sheep.

  4. Elemental composition of dog foods using nitric acid and simulated gastric digestions.

    PubMed

    Kelly, David G; White, Steven D; Weir, Ron D

    2013-05-01

    Eighteen dry dog foods obtained commercially in the United States were digested using microwave assisted nitric acid digestion and a simulated gastric digestion. Digests were analysed for 23 elements using inductively coupled plasma-mass spectrometry. Data, expressed as dry matter concentrations, were compared to published nitric acid digestion results. Nitric acid data obtained in the present study were not statistically different from published data, with the exception of Mo, Sn, Sb, Tl and Th. However, significant differences in individual intra-sample results were observed between published studies and the present work. Simulated gastric digestions demonstrated lower extraction efficiencies (<50% nitric acid digestions) that were statistically significant. Much lower bioavailability was observed for Al, Ba and Pb. In general, elemental concentrations were determined to be lower than the appropriate Mineral Tolerance Limit or consistent with background concentrations in foodstuffs. Evaluation against Reference Doses (RfDs) showed concentrations for many elements obtained by nitric acid digestion to be above RfD levels. However, the respective simulated gastric digestion data were below or only moderately elevated above RfDs. Only arsenic displayed median and maximum concentrations at factors of five and ten above the relevant RfD. PMID:23402861

  5. Decomposition Studies of Triphenylboron, Diphenylborinic Acid and Phenylboric Acid in Aqueous Alkaline Solutions Containing Copper

    SciTech Connect

    Crawford, C.L.; Peterson, R. A.

    1997-02-11

    This report documents the copper-catalyzed chemical kinetics of triphenylboron, diphenylborinic acid and phenylboric acid (3PB, 2PB and PBA) in aqueous alkaline solution contained in carbon-steel vessels between 40 and 70 degrees C.

  6. COMPARISON OF THREE METHODS FOR MEASUREMENT OF ATMOSPHERIC NITRIC ACID AND AEROSOL NITRATE AND AMMONIUM

    EPA Science Inventory

    Three methods for measuring gaseous ambient nitric acid in the low concentration range 0-15 mcg/cum were compared under field conditions in southwestern Ontario during June 1-14, 1982. The methods employed were (1) tunable diode laser absorption, (2) a tungstic acid denuder tube,...

  7. The solvent extraction of Americium(III) by 2,6-bis[(diphenylphosphino)-methyl]pyridine N,P,P` trioxide from nitric acid and hydrochloric acid solutions

    SciTech Connect

    Bond, E.M.; Engelhardt, U.; Deere, T.P.; Rapko, B.M.; Paine, R.T.

    1997-12-31

    The liquid/liquid extractions of Am(III) from nitric acid and hydrochloric acid solutions with chloroform solutions of 2,6-bis[(diphenylphosphino)methyl]pyridine N,P,P{prime} trioxide will be described. Americium(III) extracts well from high concentration nitric acid solutions (D>3000 at 6M nitric acid) and can be back extracted from the organic phase at 0.01M Nitric Acid. Americium(III) exhibits modest extraction from hydrochloric acid solutions (D=2.2 at 5M hydrochloric acid) and can be back extracted from the organic phase at 0.1M hydrochloric acid. The ligand dependency data suggest that two ligand molecules are coordinated to americium in the nitric acid system and three ligand molecules are coordinated to the americium in the hydrochloric acid system.

  8. Influence of Acidity on Uranyl Nitrate Association in Aqueous Solutions: A Molecular Dynamics Simulation Study

    SciTech Connect

    de Almeida, Valmor F; Cui, Shengting; Khomami, Bamin; Ye, Xianggui; Smith, Rodney Bryan

    2010-01-01

    Uranyl ion complexation with water and nitrate is a key aspect of the uranium/plutonium extraction process. We have carried out a molecular dynamics simulation study to investigate this complexation process, including the molecular composition of the various complex species, the corresponding structure, and the equilibrium distribution of the complexes. The observed structures of the complexes suggest that in aqueous solution, uranyls are generally hydrated by 5 water molecules in the equatorial plane. When associating with nitrate ions, a water molecule is replaced by a nitrate ion, preserving the five-fold coordination and planar symmetry. Analysis of the pair correlation function between uranyl and nitrate suggests that nitrates bind to uranyl in aqueous solution mainly in a monodentate mode, although a small portion of bidentates occur. Dynamic association and dissociation between uranyls and nitrates take place in aqueous solution with a substantial amount of fluctuation in the number of various uranyl nitrate species. The average number of the uranyl mononitrate complexes shows a dependence on acid concentration consistent with equilibrium-constant analysis, namely, the concentration of [UO2NO3]+ increases with nitric acid concentration.

  9. TESTING OF 304L STAINLESS STEEL IN NITRIC ACID ENVIRONMENTS WITH FLUORIDES AND CHLORIDES

    SciTech Connect

    Mickalonis, J.

    2010-10-04

    Impure radioactive material processed in nitric acid solutions resulted in the presence of chlorides in a dissolver fabricated from 304L stainless steel. An experimental program was conducted to study the effects of chloride in nitric acid/fluoride solutions on the corrosion of 304L stainless steel. The test variables included temperature (80, 95, and 110 C) and the concentrations of nitric acid (6, 12, and 14 M), fluoride (0.01, 0.1, and 0.2 M) and chloride (100, 350, 1000, and 2000 ppm). The impact of welding was also investigated. Results showed that the chloride concentration alone was not a dominant variable affecting the corrosion, but rather the interaction of chloride with fluoride significantly affected corrosion.

  10. Proton affinity of methyl nitrate - Less than proton affinity of nitric acid

    NASA Technical Reports Server (NTRS)

    Lee, Timothy J.; Rice, Julia E.

    1992-01-01

    Several state-of-the-art ab initio quantum mechanical methods were used to investigate the equilibrium structure, dipole moments, harmonic vibrational frequencies, and IR intensities of methyl nitrate, methanol, and several structures of protonated methyl nitrate, using the same theoretical methods as in an earlier study (Lee and Rice, 1992) of nitric acid. The ab initio results for methyl nitrate and methanol were found to be in good agreement with available experimental data. The proton affinity (PA) of methyl nitrate was calculated to be 176.9 +/-5 kcal/mol, in excellent agreement with the experimental value 176 kcal/mol obtained by Attina et al. (1987) and less than the PA value of nitric acid. An explanation of the discrepancy of the present results with those of an earlier study on protonated nitric acid is proposed.

  11. Polymerization of beta-amino acids in aqueous solution

    NASA Technical Reports Server (NTRS)

    Liu, R.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

    1998-01-01

    We have compared carbonyl diimidazole (CDI) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as activating agents for the oligomerization of negatively-charged alpha- and beta-amino acids in homogeneous aqueous solution. alpha-Amino acids can be oligomerized efficiently using CDI, but not by EDAC. beta-Amino acids can be oligomerized efficiently using EDAC, but not by CDI. Aspartic acid, an alpha- and beta-dicarboxylic acid is oligomerized efficiently by both reagents. These results are explained in terms of the mechanisms of the reactions, and their relevance to prebiotic chemistry is discussed.

  12. Using isotope dilution mass spectrometry to determine aqueous trichloroacetic acid

    SciTech Connect

    Norwood, D.L.; Christman, R.F.; Johnson, J.D.; Hass, J.R.

    1986-01-01

    The development, verification, and application of a method based on isotope-dilution gas chromatography-mass spectrometry to determine aqueous trichloroacetic acid (TCAA) at the micrograms per litre level are described. The simultaneous determination of aqueous chloroform is also demonstrated. Trichloroacetic acid is shown to be a significant by-product of the chlorination of raw waters in the laboratory and to constitute a large fraction of the total organic halide (TOX) formed. Analysis of finished-water samples indicated that TCAA, like trihalomethanes is ubiquitous. Positive correlations exist between the levels of TCAA in laboratory-chlorinated raw waters and in finished waters and measured TOX.

  13. Studies on reaction runaways for Urex/Purex solvent-nitric acid and red-oil synthesis

    SciTech Connect

    Kumar, Shekhar; Kumar, Rajnish; Koganti, S.B.

    2008-07-01

    In PUREX/UREX processes for recycling of spent nuclear fuels, 30% TBP solvent is used, This solvent has a small solubility in the aqueous phase. During concentration of the process solutions by an evaporation route, a runaway reaction between TBP and nitric acid is initiated at above 130 deg. C, leading to rapid pressurization and finally containment failure if proper venting is not provided. Red oil was synthesized for the first time in India, and its physical properties as well as thermodynamic parameters for the reaction were determined. It was experimentally established that the presence of metallic nitrates was not essential for red-oil formation as thought earlier. Various experiments have been completed for single-phase as well as two-phase runs. The most important finding of this work was lowering of the limiting acid concentration from the conventional values. In fact, in these experiments, red oil could be formed even at 2 N aqueous acidity. Thus, safety guidelines based on the classical literature are obsolete. New guidelines for the red-oil-safety are required. (authors)

  14. Oxidation of hydroxylamine by nitrous and nitric acids. Model development from first principle SCRF calculations.

    PubMed

    Raman, Sumathy; Ashcraft, Robert W; Vial, Marc; Klasky, Marc L

    2005-09-29

    Ab initio molecular orbital calculations have been performed to develop an elementary reaction mechanism for the autocatalytic and scavenging reactions of hydroxylamine in an aqueous nitric acid medium. An improved understanding of the titled reactions is needed to determine the "stability boundary of hydroxylamine" for safe operations of the plutonium-uranium reduction extraction (PUREX) process. Under the operating conditions of the PUREX process, namely, 6 M nitric acid, the reactive forms of hydroxylamine are NH2OH, NH3OH+, and the complex NH3OH.NO3, and those of nitrous acid are NO+, H2ONO+, N2O4, N2O3, NO2, and NO. High-level CBSQB3/IEFPCM and CBSQB3/COSMO calculations were performed using GAUSSIAN03 to investigate the energy landscape and to explore a large number of possible ion-ion, ion-radical, ion-molecule, radical-radical, radical-molecule, and molecule-molecule pathways available to the reactive forms of the reactants in solution. It was found that in solution the autocatalytic generation of nitrous acid proceeds through free radical pathways at low-hydroxylamine concentrations from unprotonated NH2OH via hydrogen abstraction. At high [NH3OH+], we suggest a possible involvement of the NH3ONO+ intermediate via the reaction NH2ONO + NO2 --> HNO + HONO + NO. The NH3ONO+ intermediate, in turn, is formed favorably via the ion-ion reactions of NH3OH+ with NO+ and/or the reaction between NO+ and hydroxylammonium nitrate (HAN). The intermediates involved in the scavenging reaction of nitrous acid by hydroxylamine are NH3ONO+, NH2ONO, NH2(NO)O, NH(NO)OH, and HONNOH and the rate-determining step is the 1,2-NO migration in NH2ONO leading to NH2(NO)O. Reactions NH2ONO --> NH2(NO)O and NH2(NO)O --> NH(NO)OH were studied with two explicit water molecules and the results are discussed in the context of the importance of the explicit treatment of solvent in the determination of the energetics and mechanism of these processes. The rate constants for the reactions were

  15. Qualification Data for the Corrosion Behavior of Inconel and Steel Alloys in Nitric Acid

    SciTech Connect

    Mickalonis, J.I.

    2001-04-17

    During filling operations in the Defense Waste Processing Facility (DWPF), melter inserts made of Inconel 690 (I690) have fallen into the canisters which are made of 304L stainless steel (304L). The consequences of possible galvanic corrosion between these materials were evaluated using two electrochemical techniques. Materials for other items which might fall into the canisters were also evaluated including Inconel MA758 (MA758) and A537 carbon steel (A537). The test solutions were concentrated nitric acid, used for validating literature data, and a 10 M nitric acid solution for simulating a possible environment, which may develop due to radiolysis inside the sealed canister.

  16. Qualification Data for the Corrosion Behavior of Inconel and Steel Alloys in Nitric Acid

    SciTech Connect

    Mickalonis, J.I.

    2001-05-02

    During filling operations in the Defense Waste Processing Facility (DWPF), melter inserts made of Inconel 690 (I690) have fallen into the canisters which are made of 304L stainless steel (304L). The consequences of possible galvanic corrosion between these materials were evaluated using two electrochemical techniques. Materials for other items which might fall into the canisters were also evaluated including Inconel MA758 (MA758) and A537 carbon steel (A537). The test solutions were concentrated nitric acid, used for validating literature data, and a 10 M nitric acid solution for simulating a possible environment, which may develop due to radiolysis inside the sealed canister.

  17. Ab Initio Calculations of Singlet and Triplet Excited States of Chlorine Nitrate and Nitric Acid

    NASA Technical Reports Server (NTRS)

    Grana, Ana M.; Lee, Timothy J.; Head-Gordon, Martin; Langhoff, Stephen R. (Technical Monitor)

    1994-01-01

    Ab initio calculations of vertical excitations to singlet and triplet excited states of chlorine nitrate and nitric acid are reported. The nature of the electronic transitions are examined by decomposing the difference density into the sum of detachment and attachment densities. Counterparts for the three lowest singlet excited states of nitric acid survive relatively unperturbed in chlorine nitrate, while other low-lying singlet states of chlorine nitrate appear to be directly dissociative in the ClO chromophore. These results suggest an assignment of the two main peaks in the experimental chlorine nitrate absorption spectrum. In addition, triplet vertical excitations and the lowest optimized triplet geometries of both molecules are studied.

  18. Kinetics of the reaction of adamantane and its derivatives with nitric acid

    SciTech Connect

    Klimochkin, Yu.N.; Moiseev, I.K.

    1988-08-10

    The reaction of adamantane compounds with nitric acid in methylene chloride is of first order with respect to the substrate, and its rate is proportional to the fifth power of the nitric acid concentration. A considerable kinetic isotope effect was found (4.4 /plus minus/ 0.3). The rate constants are linearly related to the solvolysis rate constants of the corresponding bromine derivatives and the Taft induction constants. A possible mechanism for oxynitration, including the removal of a hydride ion as controlling stage is proposed.

  19. Relative contributions of sulfuric and nitric acids in acid rain to the acidification of the ecosystem: implications for control strategies

    SciTech Connect

    McLean, R.A.N.

    1981-11-01

    Much of northeastern North America has been receiving precipitation of pH 4.6 or less, i.e. more than ten times more acid than normal rain (pH = 5.6) for at least the past 20 to 30 years. Originally, this acidity was almost totally due to sulfuric acid. These inputs of sulfuric acid in the very acid sensitive Adirondacks may have removed much of the neutralizing and nitrate-utilizing ability of the soils and water. Thus, this area may now be more sensitive to atmospheric inputs of nitric acid. Further work is required on the impact of acid nitrate deposition on the ecosystem but with equal certainty it can be stated that sulfur deposition remains the princpial long term threat to acid sensitive ecosystems. It can be concluded that: much of the nitric acid in acid rain is decomposed in the soils and waterway, and is not a significant contributor to long-term acidification of soils and waters; although in the long term, nitric acid in atmospheric deposition is not likely to be contributing to the overall acidification of the environment, during the spring thaw, in areas which have been heavily impacted by acid rain for a number of years, nitric acid which has concentrated in the snow pack over the winter may cause ecological damage, especially to fish populations; though there is little doubt that tighter control strategies are necessary to diminish the effects of acid rain on remote ecosystems the existing control strategies, which have put more emphasis on the control of emissions of sulfur oxides than nitrogen oxides, have a reasonable scientific basis given our present limited knowledge of their effects on the ecosystem.

  20. Material compatibility evaluation for DWPF nitric-glycolic acid-literature review

    SciTech Connect

    Mickalonis, J.; Skidmore, E.

    2013-06-01

    Glycolic acid is being evaluated as an alternative for formic and nitric acid in the DWPF flowsheet. Demonstration testing and modeling for this new flowsheet has shown that glycolic acid and glycolate has a potential to remain in certain streams generated during the production of the nuclear waste glass. A literature review was conducted to assess the impact of glycolic acid on the corrosion of the materials of construction for the DWPF facility as well as facilities downstream which may have residual glycolic acid and glycolates present. The literature data was limited to solutions containing principally glycolic acid.

  1. Raman spectra of amino acids and their aqueous solutions

    NASA Astrophysics Data System (ADS)

    Zhu, Guangyong; Zhu, Xian; Fan, Qi; Wan, Xueliang

    2011-03-01

    Amino acids are the basic "building blocks" that combine to form proteins and play an important physiological role in all life-forms. Amino acids can be used as models for the examination of the importance of intermolecular bonding in life processes. Raman spectra serve to obtain information regarding molecular conformation, giving valuable insights into the topology of more complex molecules (peptides and proteins). In this paper, amino acids and their aqueous solution have been studied by Raman spectroscopy. Comparisons of certain values for these frequencies in amino acids and their aqueous solutions are given. Spectra of solids when compared to those of the solute in solution are invariably much more complex and almost always sharper. We present a collection of Raman spectra of 18 kinds of amino acids ( L-alanine, L-arginine, L-aspartic acid, cystine, L-glutamic acid, L-glycine, L-histidine, L-isoluecine, L-leucine, L-lysine, L-phenylalanine, L-methionone, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine, L-valine) and their aqueous solutions that can serve as references for the interpretation of Raman spectra of proteins and biological materials.

  2. Persistent Ion Pairing in Aqueous Hydrochloric Acid

    SciTech Connect

    Baer, Marcel D.; Fulton, John L.; Balasubramanian, Mahalingam; Schenter, Gregory K.; Mundy, Christopher J.

    2014-07-03

    For strong acids, like hydrochloric acid, the complete dissociation into an excess proton and conjugated base as well as the formation of independent solvated charged fragments is assumed. The existence of a chloride-Hyronium (Cl-H3O+) contact ion pairs even in moderate concentration hydrochloric acid (2.5 m) demonstrates that the counter ions do not behave merely as spectators. Through the use of modern extended X-ray absorption fine structure (EXAFS) measurements in conjunction with state-of-the-art density functional theory (DFT) simulations, we are able to obtain an unprecedented view into the molecular structure of medium to high concentrated electrolytes. Here we report that the Cl-H3O+ contact ion pair structure persists throughout the entire concentration range studied and that these structures differ significantly from moieties studied in micro-solvated hydrochloric acid clusters. Characterizing distinct populations of these ion pairs gives rise to a novel molecular level description of how to think about the activity of the proton that impacts our picture of the pH scale. Funding for CJM, GKS, and JLF was provided by DOE Office of Science, Office of Basic Energy Science, Division of Chemical Sciences, Geosciences, and Biosciences. Funding for MDB was provided throught the Laboratory Directed Research and Development program at Pacific Northwest National Laboratory. MB was funded through Argonne National Laboratory.

  3. Electrolytic recovery of copper and regeneration of nitric acid from a copper strip solution

    SciTech Connect

    Stewart, T.L.; Hartley, J.N.

    1985-01-01

    The fabrication of nuclear fuels involves stripping of a copper jacket with nitric acid. The waste acid, which contains 3.0 to 4.5 N nitric acid and 100 to 180 g/L copper, is currently discharged, neutralized, and disposed of in solar evaporation ponds. Alternative waste disposal and treatment methods including electrowinning are being investigated. Laboratory-scale electrowinning tests have been conducted in an air-sparged cell at current densities from 0.027 to 0.22 A/cm/sup 2/. The efficiency of copper recovery was improved by adding sulfamic acid or by cooling the electrolyte. Copper current efficiency ranged from 55% to 95%; energy consumption ranged from 1.8 to 6.6 kWh/kg Cu. Results of the laboratory-scale electrowinning tests are summarized. A brief economic comparison of an alternative waste disposal and acid recycle technique is presented.

  4. Amino-acid contamination of aqueous hydrochloric acid.

    NASA Technical Reports Server (NTRS)

    Wolman, Y.; Miller, S. L.

    1971-01-01

    Considerable amino-acid contamination in commercially available analytical grade hydrochloric acid (37% HCl) was found. One bottle contained 8,300 nmol of amino-acids per liter. A bottle from another supplier contained 6,700 nmol per liter. The contaminants were mostly protein amino-acids and several unknowns. Data on the volatility of the amino-acids during HCl distillation were also obtained.

  5. Mercury-free dissolution of aluminum-clad fuel in nitric acid

    SciTech Connect

    Christian, J.D.; Anderson, P.A.

    1993-12-31

    It is the purpose of this invention to provide a continuous optimum process for the dissolution of aluminum, without the use of a mercury catalyst. Ile invention generally stated is: a process for dissolution of aluminum comprising: preparing a mixture of nitric acid`and fluoboric acid in a makeup vessel or individual reagents in separate vessels; placing an aluminum element in a dissolver vessel having an overflow; transferring a portion of the mixture of nitric acid and fluoboric acid to the dissolver vessel from the makeup vessel; heating the dissolver vessel and mixture to a boiling temperature and holding that temperature until a desired concentration of dissolved aluminum is achieved; adding a constant flow influent of the mixture of nitric acid and fluoboric acid to the dissolver vessel; and collecting an effluent from the dissolver vessel overflow, said effluent containing a mixture of aluminum nitrate, nitric acid, fluoboric acid, water, and dissolved fuel components. The variables in the above process can be temperature, effluent flow rate, and concentration of the acids as will be discussed later. For corrosion control, it may be necessary to initiate reaction at a decreased HNO{sub 3} concentration and to increase it after a sufficient concentration of aluminum nitrate has accrued. The process may be adapted to batch processing, as well. Again, acid concentrations may be initially relatively small and, then, gradually increased as reaction proceeds until the desired excess of HNO{sub 3} above stoichiometric quantity has been added. Other objects, advantages, and capabilities of the present invention will become more apparent as the description proceeds.

  6. NITRIC ACID-AIR DIFFUSION COEFFICIENT: EXPERIMENTAL DETERMINATION

    EPA Science Inventory

    Trace gaseous HNO3 in air is removed in a laminar flow nylon tube. The HNO3 deposition pattern was obtained by sectioning the tube, extracting with an aqueous solution, and measuring the concentration by ion chromatography. Mass transport analysis of the deposition pattern demons...

  7. CHARACTERIZATION OF H CANYON CONDUCTIVITY METER INDICATIONS WITH ELEVATED URANIUM IN NITRIC ACID

    SciTech Connect

    Nash, C

    2007-10-31

    Solution conductivity data from the 1CU conductivity meter in H-Canyon shows that uranium concentration in the 0 to 30 gram per liter (g/L) range has no statistically significant effect on the calibration of free nitric acid measurement. Based on these results, no additional actions are needed on the 1CU Conductivity Meter prior to or during the processing of uranium solutions in the 0 to 30 g/L range. A model based only on free nitric acid concentration is shown to be appropriate for explaining the data. Data uncertainties for the free acid measurement of uranium-bearing solutions are 8.5% or less at 95% confidence. The analytical uncertainty for calibrating solutions is an order of magnitude smaller only when uranium is not present, allowing use of a more accurate analytical procedure. Literature work shows that at a free nitric acid level of 0.33 M, uranium concentration of 30 g/L and 25 C, solution conductivity is 96.4% of that of a uranium-free solution. The level of uncertainties in the literature data and its fitting equation do not justify calibration changes based on this small depression in solution conductivity. This work supports preparation of H-Canyon processing of Super Kukla fuel; however, the results will be applicable to the processing of any similar concentration uranium and nitric acid solution. Super Kukla fuel processing will increase the uranium concentration above the nominal zero to 10 g/L level, though not above 30 g/L. This work examined free nitric acid levels ranging from 0.18 to 0.52 molar. Temperature ranged from 27.9 to 28.3 C during conductivity testing. The data indicates that sequential order of measurement is not a significant factor. The conductivity meter was thus flushed effectively between measurements as desired.

  8. GASEOUS AND PARTICULATE AMMONIA AND NITRIC ACID CONCENTRATIONS, COLUMBUS, OHIO AREA--SUMMER 1980

    EPA Science Inventory

    Data is presented for gaseous ammonia and nitric acid and particulate ammonium ion and nitrate ion concentrations in air samples collected in support of the PEPE-NEROS study during the summer of 1980. Ground-level samples were collected near Croton, Ohio; aerial samples were also...

  9. NITRIC ACID-NITRATE AEROSOL MEASUREMENTS BY A DIFFUSION DENUDER: A PERFORMANCE EVALUATION

    EPA Science Inventory

    A nitric acid diffusion denuder made of nylon was operated in Riverside, CA, Houston, TX, and Claremont, CA. The pre-exponential and diffusion coefficients for the first term of the Gormley-Kennedy equation were estimated by regressing the log (mass deposited) against the axial d...

  10. 77 FR 48433 - New Source Performance Standards Review for Nitric Acid Plants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-14

    ... Federal Register on December 23, 1971 (36 FR 24881). The first review of the Nitric Acid Plants NSPS was completed on June 19, 1979 (44 FR 35265). An additional review was completed on April 5, 1984 (49 FR 13654... were made during three reviews since the original promulgation in 1971 (October 6, 1975 (40 FR...

  11. 76 FR 63878 - New Source Performance Standards Review for Nitric Acid Plants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-14

    ..., Subpart G) were promulgated in the Federal Register on December 23, 1971 (36 FR 24881). The first review of the Nitric Acid Plants NSPS was completed on June 19, 1979 (44 FR 35265). An additional review was completed on April 5, 1984 (49 FR 13654). No changes were made to the NSPS as a result of those...

  12. 46 CFR 153.559 - Special requirements for nitric acid (less than 70 percent).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Special requirements for nitric acid (less than 70 percent). 153.559 Section 153.559 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements...

  13. 46 CFR 153.559 - Special requirements for nitric acid (less than 70 percent).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Special requirements for nitric acid (less than 70 percent). 153.559 Section 153.559 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements...

  14. K Basin Sludge Conditioning Testing: Nitric Acid Dissolution Testing of K East Canister Sludge

    SciTech Connect

    Carlson, C.D.; Delegard, C.H.; Burgeson, I.E.: Schmidt, A.J.; Bredt, P.R.; Silvers, K.L.

    1999-04-01

    This report describes tests performed by Pacific Northwest National Laboratory (PNNL) for Numatec Hanford Corporation (NHC) as part of the overall activities for the development of the K Basin Sludge Treatment System. These tests were conducted to examine the dissolution behavior of a K East Basin canister sludge composite in nitric acid at the following concentrations: 2 M, 4 M, 6 M, 7.8 M and 10 M and temperatures of 25 C and boiling. Assuming that the sludge was 100% uranium metal, a 4X stoichiometric excess of nitric acid was used for all testing, except that conducted at 4 M. In the 4 M nitric acid dissolution test, 50% excess nitric acid was used resulting in a dissolver solution with a significantly higher solids loading. The boiling tests were conducted for 11 hr, the 25 C dissolution tests were conducted from 24 hr to 2 weeks. For the 25 C dissolution testing, the weight percent residual solids was determined, however, chemical and radiochemical analyses were not performed.

  15. The FB-Line and F-Canyon HAN/Nitric Acid Decomposition Study

    SciTech Connect

    Hang, T.

    1998-08-19

    Separations requested SRTC study the autocatalytic decomposition of the hydroxylamine nitrate which may occur in the presence of concentrated nitric acid with respect to making-up cold feed solutions. The data obtained from this study will provide Separations an envelope within which safe operations can be conducted.

  16. [Case of dyspnea due to toilet cleaner containing nitric acid for household use].

    PubMed

    Yanagawa, Youichi; Matsukawa, Takehisa; Yokoyama, Kazuhito; Hirano, Yohei; Ri, Tetsunari; Aihara, Koichiro; Iba, Toshiaki; Tanaka, Hiroshi

    2013-09-01

    A 40-year-old male tried to clean a urinal at his home storing 900 mL of a toilet cleaner containing 9.8% nitric acid to remove calcium deposit, and clean the toilet floor for twenty minutes. Immediately after using the cleaner, he experienced eye irritation. He washed out the toilet cleaner. However, he thereafter experienced dyspnea, a compressive sensation in his chest, and chest and back pain about 40 minutes after the cleaning the toilet. He monitored his symptoms overnight and found them to gradually improve. However, the symptoms still remained the next morning and therefore he came to our department on foot. He had no particular past or family history. On arrival, his physiological findings and chest computed tomography scan were negative for any abnormalities. His arterial blood gas analysis revealed a mild abnormality of oxygenation. Observation without any drugs revealed that a complete remission of his symptoms occurred after approximately 4 weeks. Based on the results of the experiments, contact with the mucosal membrane and nitric acid gas produced by any accidentally coexisting metals or contact with moisture, including nitric acid produced by a reaction between CaCO3 and cleaner, may have been the mechanism of occurrence for the symptoms observed in this case. This is the first reported case of nitric acid poisoning due to the use of a toilet cleanser intended for household use. PMID:24224389

  17. Dissolution of sludges containing uranium dioxide and metallic uranium in nitric acid

    SciTech Connect

    Flament, T.A.

    1998-08-25

    The dissolution in nitric acid of sludges containing uranium oxide and uranium has been modeled. That study has shown that it was necessary to continuously feed the dissolver to have an appropriate control of the reaction. If a unique procedure is deemed preferable, NH03 6M has been used.

  18. Nitric acid-organic mixtures surveyed for use in separation by anion exchange methods

    NASA Technical Reports Server (NTRS)

    Bloomquist, C. A. A.; Faris, J. P.; Stewart, D. C.

    1968-01-01

    Column elution-spectrographic analysis technique compares certain solvents directly to the methanol system, using inert rare earths instead of actinides. Distribution ratios for americium between 90 percent solvent, 10 percent 5 M nitric acid and Dowex 1 nitrate form resin for a large group of organics miscible in water was determined.

  19. Ultrasonic cleaning of depleted uranium material as an alternative to nitric acid cleaning

    SciTech Connect

    Frye, L.E.; Senviel, C.B.

    1991-05-28

    Nitric acid is used to clean depleted uranium in the form of cast billets, and cast and wrought parts in the processing cycle and is the largest contributor of waste to the West End Treatment Facility (WETF). An estimated 27,000 gallons of liquid and 75 to 95% of all uranium received was sent to the WETF for processing from this facility in our baseline year. Because wrought parts account for the largest throughput at the nitric acid facility, an alternative cleaning method for these parts was examined first. Test results on the first part type from the wrought family showed ultrasonic cleaning to be an effective cleaning method. Since the geometry for this part presented the most difficulty in terms of ultrasonic cleaning, the entire wrought family is expected to be moved from the nitric acid facility to the ultrasonic cleaning facility. As a result, there will be an 83% reduction part throughput at the nitric acid facility which corresponds to a significant decrease in wastes sent to the WETF and a reduction in the generation and associated costs of waste overall. This change also eliminated two building moves involving two RAD areas resulting in a part movement reduction of approximately 25% which is a significant cost savings.

  20. Extraction of Palladium from Nitric Acid by Diamides of Di-picolinic Acid

    SciTech Connect

    Alyapyshev, M.Yu.; Babain, V.A.; Pokhitonov, Yu.A.; Esimantovskiy, V.M.

    2007-07-01

    The most complicated and urgent problem of atomic industry consists in the safe isolation and storage of radioactive wastes. The long-lived radionuclides presented in high-level liquid wastes (HLLW) pose a potential threat to environment for hundreds and thousands of years. One of the possible ways to reduce the danger of HLLW storages is concerned with treatment of HLLW intended to recovery of long-lived radionuclides and their partitioning into separate fractions. The separation of the most hazardous radionuclides (like transplutonium elements (TPE)) to the individual fraction of low volume leads to decrease of the total volume of HLLW and therefore to decrease of solidified waste storage costs. It should be noted that only in the case of reprocessing it can be possible to recover individual radionuclides (or their fractions) into separate flows with further special approach to each of them. Partitioning of different HLLW is under investigation in many countries now. Numerous processes for recovery of Cs, Sr, TPE and REE have been already developed and tested. At the same time partitioning is only the first step on the road to the following synthesis of materials providing the safe storage of long-lived radionuclides over many thousands of years. The metallic palladium contained in HLLW seems to be a promising material for producing of matrices for incorporation of radioactive wastes. Different methods for palladium recovery have been investigated: reductive precipitation, electrochemical precipitation, sorption and extraction. Of prime importance are extraction methods. Phosphine oxides, carbamoyl-phosphine oxides, crown-ethers, oximes, sulfides and some other compounds were proposed as extractants towards palladium from nitric acid media. It is reasonable to recover palladium into individual fraction during waste partitioning. Diamides of malonic, di-glycolic and pyridine-dicarboxylic (di-picolinic) acids are intensively investigated as extractants for HLLW

  1. Tropospheric nitric acid columns from the IASI satellite instrument interpreted with a chemical transport model: Implications for parameterizations of nitric oxide production by lightning

    NASA Astrophysics Data System (ADS)

    Cooper, Matthew; Martin, Randall V.; Wespes, Catherine; Coheur, Pierre-Francois; Clerbaux, Cathy; Murray, Lee T.

    2014-08-01

    This paper interprets tropical tropospheric nitric acid columns from the Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument with a global chemical transport model (GEOS-Chem). GEOS-Chem and IASI columns generally agree over the tropical ocean to within 10%. However, the GEOS-Chem simulation underestimates IASI nitric acid over Southeast Asia by a factor of 2. The regional nitric acid bias is confirmed by comparing the GEOS-Chem simulation with additional satellite (High Resolution Dynamics Limb Sounder, Atmospheric Chemistry Experiment Fourier Transform Spectrometer) and aircraft (Pacific Exploratory Mission (PEM)-Tropics A and PEM-West B) observations of the middle and upper troposphere. This bias appears to be driven by the lightning NOx parameterization, both in terms of the magnitude of the NOx source and the ozone production efficiency of concentrated lightning NOx plumes. We tested a subgrid lightning plume parameterization and found that an ozone production efficiency of 15 mol/mol in lightning plumes over Southeast Asia in conjunction with an additional 0.5 Tg N would reduce the regional nitric acid bias from 92% to 6% without perturbing the rest of the tropics. Other sensitivity studies such as modified NOx yield per flash, increased altitude of lightning NOx emissions, decreased convective mass flux, or increased scavenging of nitric acid required unrealistic changes to reduce the bias.

  2. Conductance Studies on Aqueous Citric Acid

    NASA Astrophysics Data System (ADS)

    Apelblat, Alexander; Barthel, Josef

    1991-02-01

    Conductance measurements of citric acid and neutral citrates (tri-lithium citrate, tri-sodium citrate and tri-potassium citrate) were performed in water at 278.15 to 308.15 K. The equilibrium constants for the primary and secondary steps of dissociation, Kx and K2, and the limiting conductances, λ0(H2Cit-), λ°(1/2 HCit2-), and λ0(1/3 Cit3-) are reported as a function of temperature. They are obtained by application of the Quint and Viallard conductance equation. The enthalpies of dissociation are estimated.

  3. The Consistency of Isotopologues of Ambient Atmospheric Nitric Acid in Passively Collected Samples

    NASA Astrophysics Data System (ADS)

    Bell, M. D.; Sickman, J. O.; Bytnerowicz, A.; Padgett, P.; Allen, E. B.

    2012-12-01

    Anthropogenic sources of nitrogen oxides have previously been shown to have distinctive isotopic signatures of oxygen and nitrogen. Nylon filters are currently used in passive sampling arrays to measure ambient atmospheric nitric acid concentrations and estimate deposition rates. This experiment measured the ability of nylon filters to consistently collect isotopologues of atmospheric nitric acid in the same ratios as they are present in the atmosphere. Samplers were deployed in continuous stirred tank reactors (CSTR) and at field sites across a nitrogen deposition gradient in Southern California. Filters were exposed over a four week period with individual filters being subjected to 1-4 week exposure times. Extracted nitric acid were measured for δ18O and δ15N ratios and compared for consistency based on length of exposure and amount of HNO3 collected. Filters within the CSTRs collected HNO3 at a consistent rate in both high and low concentration chambers. After two weeks of exposure, the mean δ18O values were within 0.5‰ of the δ18O of the source HNO3 solution. The mean of all weekly exposures were within 0.5‰ of the δ15N of the source solution, but after three weeks, the mean δ15N of adsorbed HNO3 was within 0.2‰. As the length of the exposure increased, the variability of measured delta values decreased for both elements. The field samplers collected HNO3 consistent with previously measured values along a deposition gradient. The mean δ18O at high deposition sites was 52.2‰ compared to 35.7‰ at the low deposition sites. Mean δ15N values were similar at all sites across the deposition gradient. Due to precipitation events occurring during the exposure period, the δ15N and δ18O of nitric acid were highly variable at all field sites. At single sites, changes in δ15N and δ18O were negatively correlated, consistent with two-sourcing mixing dynamics, but the slope of the regressions differed between high and low deposition sites. Anthropogenic

  4. Nitric acid treated multi-walled carbon nanotubes optimized by Taguchi method

    NASA Astrophysics Data System (ADS)

    Shamsuddin, Shahidah Arina; Derman, Mohd Nazree; Hashim, Uda; Kashif, Muhammad; Adam, Tijjani; Halim, Nur Hamidah Abdul; Tahir, Muhammad Faheem Mohd

    2016-07-01

    Electron transfer rate (ETR) of CNTs can be enhanced by increasing the amounts of COOH groups to their wall and opened tips. With the aim to achieve the highest production amount of COOH, Taguchi robust design has been used for the first time to optimize the surface modification of MWCNTs by nitric acid oxidation. Three main oxidation parameters which are concentration of acid, treatment temperature and treatment time have been selected as the control factors that will be optimized. The amounts of COOH produced are measured by using FTIR spectroscopy through the absorbance intensity. From the analysis, we found that acid concentration and treatment time had the most important influence on the production of COOH. Meanwhile, the treatment temperature will only give intermediate effect. The optimum amount of COOH can be achieved with the treatment by 8.0 M concentration of nitric acid at 120 °C for 2 hour.

  5. γ-Irradiation of malic acid in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Negron-Mendoza, Alicia; Graff, Rebecca L.; Ponnamperuma, Cyril

    1980-12-01

    The γ-irradiation of malic acid in aqueous solutions was studied under initially oxygenated and oxygen-free conditions in an attempt to determine the possible interconversion of malic acid into other carboxylic acids, specifically those associated with Krebs cycle. The effect of dose on product formation of the system was investigated. Gas-liquid chromatography combined with mass spectrometry was used as the principal means of identification of the non-volatile products. Thin layer chromotography and direct probe mass spectroscopy were also employed. The findings show that a variety of carboxylic acids are formed, with malonic and succinic acids in greatest abundance. These products have all been identified as being formed in the γ-irradiation of acetic acid, suggesting a common intermediary. Since these molecules fit into a metabolic cycle, it is strongly suggestive that prebiotic pathways provided the basis for biological systems.

  6. On the growth of nitric and sulfuric acid aerosol particles under stratospheric conditions

    NASA Technical Reports Server (NTRS)

    Hamill, Patrick; Turco, R. P.; Toon, O. B.

    1988-01-01

    A theory for the formation of frozen aerosol particles in the Antarctic stratosphere was developed and applied to the formation of polar stratospheric clouds. The theory suggests that the condensed ice particles are composed primarily of nitric acid and water, with small admixtures of sulfuric and hydrochloric acids in solid solution. The proposed particle formation mechanism is in agreement with the magnitude and seasonal behavior of the optical extinction observed in the winter polar stratosphere.

  7. Investigation of acyl migration in mono- and dicaffeoylquinic acids under aqueous basic, aqueous acidic, and dry roasting conditions.

    PubMed

    Deshpande, Sagar; Jaiswal, Rakesh; Matei, Marius Febi; Kuhnert, Nikolai

    2014-09-17

    Acyl migration in chlorogenic acids describes the process of migration of cinnamoyl moieties from one quinic acid alcohol group to another, thus interconverting chlorogenic acid regioisomers. It therefore constitutes a special case of transesterification reaction. Acyl migration constitutes an important reaction pathway in both coffee roasting and brewing, altering the structure of chlorogenic acid initially present in the green coffee bean. In this contribution we describe detailed and comprehensive mechanistic studies comparing inter- and intramolecular acyl migration involving the seven most common chlorogenic acids in coffee. We employe aqueous acidic and basic conditions mimicking the brewing of coffee along with dry roasting conditions. We show that under aqueous basic conditions intramolecular acyl migration is fully reversible with basic hydrolysis competing with acyl migration. 3-Caffeoylquinic acid was shown to be most labile to basic hydrolysis. We additionally show that the acyl migration process is strongly pH dependent with increased transesterification taking place at basic pH. Under dry roasting conditions acyl migration competes with dehydration to form lactones. We argue that acyl migration precedes lactonization, with 3-caffeoylquinic acid lactone being the predominant product. PMID:25116442

  8. Process for the extraction of strontium from acidic solutions

    DOEpatents

    Horwitz, E.P.; Dietz, M.L.

    1993-01-01

    The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid.

  9. Process for the extraction of strontium from acidic solutions

    DOEpatents

    Horwitz, E.P.; Dietz, M.L.

    1994-09-06

    The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid. 4 figs.

  10. Process for the extraction of strontium from acidic solutions

    DOEpatents

    Horwitz, E. Philip; Dietz, Mark L.

    1994-01-01

    The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid.

  11. Vanillic acid prevents the deregulation of lipid metabolism, endothelin 1 and up regulation of endothelial nitric oxide synthase in nitric oxide deficient hypertensive rats.

    PubMed

    Kumar, Subramanian; Prahalathan, Pichavaram; Saravanakumar, Murugesan; Raja, Boobalan

    2014-11-15

    Hypertension is one of the main factors causing cardiovascular diseases. The present study was designed to evaluate the protective effect of vanillic acid against nitric oxide deficient rats. Hypertension was induced in adult male albino rats of Wistar strain, weighing 180-220g, by oral administration of N(ω)-nitro-l arginine methyl ester (l-NAME) 40mg/kg in drinking water for 4 weeks. Vanillic acid was administered orally at a dose of 50mg/kg b.w. Nitric oxide deficient rats showed increased levels of mean arterial pressure (MAP), heart rate (HR) and decreased heart nitric oxide metabolites (NOx). A significant increase in the levels of plasma cholesterol, low density lipoprotein-cholesterol (LDL-C), very low density lipoprotein-cholesterol (VLDL-C), triglycerides (TG), free fatty acids (FFA), phospholipids (PL), 3-hydroxy 3-methylglutaryl coenzyme A (HMG-CoA) reductase in the plasma, liver and kidney and decreased level of high density lipoprotein-cholesterol (HDL-C) are observed, whereas there is a decrease in the activities of plasma lipoprotein lipase (LPL) and lecithin cholesterol acyl transferase (LCAT) in nitric oxide deficient rats. l-NAME rats also showed an increase in TC, TG, FFA and PL levels in the liver and kidney tissues. Vanillic acid treatment brought the above parameters towards near normal level. Moreover the down regulated endothelial nitric oxide synthase (eNOS) and up regulated expression of endothelin 1 (ET1) components was also attenuated by vanillic acid treatment. All the above outcomes were confirmed by the histopathological examination. These results suggest that vanillic acid has enough potential to attenuate hypertension, dyslipidemia and hepatic and renal damage in nitric oxide deficient rats. PMID:25239071

  12. Laboratory studies of the formation of polar stratospheric clouds: Nitric acid condensation on thin sulfuric acid films

    NASA Astrophysics Data System (ADS)

    Iraci, Laura T.; Middlebrook, Ann M.; Tolbert, Margaret A.

    1995-10-01

    Thin sulfuric acid films were exposed to 5 × 10-8 - 8 × 10-7 torr HNO3 and 2 - 3 × 10-4 torr H2O and cooled to temperatures near the ice frost point. Fourier transform infrared (FTIR) spectroscopy was used to probe the condensed-phase species during isothermal experiments, and gas pressures were monitored with mass spectrometry. Supercooled liquid sulfuric acid films exposed to HNO3 (6 ≤ SNAT ≤ 114) showed indications of HNO3 uptake to form ternary solutions of approximately 4 wt % HNO3, 38 wt % H2SO4, and 59 wt % H2O, followed by crystallization of nitric acid trihydrate (NAT). NAT crystallization did not initiate significant crystallization of the supercooled H2SO4, but the H2SO4 often crystallized to sulfuric acid tetrahydrate (SAT) upon warming. In contrast, when crystalline SAT films were exposed to HNO3 and water, NAT did not condense within several hours, even at HNO3 saturation ratios of 30 or higher. Calculations of the contact parameter from experimental data indicate that m <0.76 for NAT on SAT. Our film studies suggest that crystalline polar stratospheric cloud (PSC) growth is most easily accomplished when stratospheric sulfate aerosols (SSAs) remain liquid, absorb HNO3, and produce crystalline nitric acid trihydrate via heterogeneous nucleation. If SSAs crystallize to SAT at some point during the winter, nitric acid condensation is hindered, and PSC formation could become more difficult.

  13. Improvement in electrochemical capacitance of activated carbon from scrap tires by nitric acid treatment

    NASA Astrophysics Data System (ADS)

    Han, Yan; Zhao, Ping-Ping; Dong, Xiao-Ting; Zhang, Cui; Liu, Shuang-Xi

    2014-12-01

    Activated carbon (AC) obtained from the industrial pyrolytic tire char is treated by concentrated nitric acid (AC-HNO3) and then used as the electrode material for supercapacitors. Surface properties and electrochemical capacitances of AC and ACHNO3 are studied. It is found that the morphology and the porous texture for AC and AC-HNO3 have little difference, while the oxygen content increases and functional groups change after the acid treatment. Electrochemical results demonstrate that the AC-HNO3 electrode displays higher specific capacitance, better stability and cycling performance, and lower equivalent series resistance, indicating that AC obtained from the industrial pyrolytic tire char treated by concentrated nitric acid is applicable for supercapacitors.

  14. Real refractive indices of infrared-characterized nitric-acid/ice films: Implications for optical measurements of polar stratospheric clouds

    NASA Technical Reports Server (NTRS)

    Middlebrook, Ann M.; Berland, Brian S.; George, Steven M.; Tolbert, Margaret A.; Toon, Owen B.

    1994-01-01

    The infrared spectra of nitric-acid/ice films representative of polar stratospheric clouds (PSCs) were collected with simultaneous optical interference measurements to determine the real refractive indices at lambda = 632 nm. Ice and amphorous nitric-acid/ice films were prepared by condensation of water and nitric acid vapors onto a wedged Al2O3 substrate. The real refractive indices of these films were determined from the optical interference of a reflected helium-neon laser during film growth. The indices of the amphorous films varied smoothly from n = 1.30 for ice to n = 1.49 for nitric acid, similar to observations in previous work. We were unable to obtain the refractive index of crystlline films during adsorption because of optical scattering caused by surface roughness. Therefore crystlline nitric acid hydrate films were prepared by annealing amphorous nitric-acid/ice films. Further heating caused desorption of the crystalline hydrate films. During desorption, the refractive indices for ice, NAM (nitric acid monohydrate), alpha- and beta-NAT (nitric acid trihydrate) films were measured using the optical interference technique. In agreement with earlier data, the real refractive indices for ice and NAM determined in desorption were n = 1.30 +/- 0.01 and n = 1.53 +/- 0.03, respectively. The real refractive indices for alpha- and beta-NAT were found to be n = 1.51 +/- 0.01 and n greater than or equal to 1.46, respectively. Our measurements also suggest that the shape of crystalline nitric acid particles may depend on whether they nucleate from the liquid or by vapor deposition. If confirmed by future studies, this observation may provide a means of distinguishing the nucleation mechanism of crystalline PSCs.

  15. Solubility of chlorine in aqueous hydrochloric acid solutions.

    PubMed

    Alkan, Mahir; Oktay, Münir; Kocakerim, M Muhtar; Copur, Mehmet

    2005-03-17

    The solubility of chlorine in aqueous hydrochloric acid solutions was studied. The effects of HCl concentration and temperature on the solubility were evaluated, and the thermodynamic parameters of the dissolution were calculated. It was found that the solubility isotherms had a minimum at about 0.5M HCl concentration at all the temperatures studied and that solubility decreased with the increase of temperature at all the HCl concentration range investigated. PMID:15752843

  16. LIMS Instrument Package (LIP) balloon experiment: Nimbus 7 satellite correlative temperature, ozone, water vapor, and nitric acid measurements

    NASA Technical Reports Server (NTRS)

    Lee, R. B., III; Gandrud, B. W.; Robbins, D. E.; Rossi, L. C.; Swann, N. R. W.

    1982-01-01

    The Limb Infrared Monitor of the Stratosphere (LIMS) LIP balloon experiment was used to obtain correlative temperature, ozone, water vapor, and nitric acid data at altitudes between 10 and 36 kilometers. The performance of the LIMS sensor flown on the Nimbus 7 Satellite was assessed. The LIP consists of the modified electrochemical concentration cell ozonesonde, the ultraviolet absorption photometric of ozone, the water vapor infrared radiometer sonde, the chemical absorption filter instrument for nitric acid vapor, and the infrared radiometer for nitric acid vapor. The limb instrument package (LIP), its correlative sensors, and the resulting data obtained from an engineering and four correlative flights are described.

  17. Mediated electrochemical oxidation of organic wastes using a Co (III) mediator in a nitric acid based system

    DOEpatents

    Balazs, G.B.; Chiba, Z.; Lewis, P.R.; Nelson, N.; Steward, G.A.

    1999-06-15

    An electrochemical cell with a Co(III) mediator and nitric acid electrolyte provides efficient destruction of organic and mixed wastes. The organic waste is concentrated in the anolyte reservoir, where the mediator oxidizes the organics and insoluble transuranic compounds and is regenerated at the anode until the organics are converted to CO[sub 2]. The nitric acid is an excellent oxidant that facilitates the destruction of the organic components. The anode is not readily attacked by the nitric acid solution, thus the cell can be used for extended continual operation without electrode replacement. 2 figs.

  18. Mediated electrochemical oxidation of organic wastes using a Co (III) mediator in a nitric acid based system

    DOEpatents

    Balazs, G. Bryan; Chiba, Zoher; Lewis, Patricia R.; Nelson, Norvell; Steward, G. Anthony

    1999-01-01

    An electrochemical cell with a Co(III) mediator and nitric acid electrolyte provides efficient destruction of organic and mixed wastes. The organic waste is concentrated in the anolyte reservoir, where the mediator oxidizes the organics and insoluble transuranic compounds and is regenerated at the anode until the organics are converted to CO.sub.2. The nitric acid is an excellent oxidant that facilitates the destruction of the organic components. The anode is not readily attacked by the nitric acid solution, thus the cell can be used for extended continual operation without electrode replacement.

  19. A laboratory study of the nucleation kinetics of nitric acid hydrates under stratospheric conditions

    NASA Astrophysics Data System (ADS)

    James, Alexander D.; Murray, Benjamin J.; Plane, John M. C.

    2016-04-01

    Measurements of the kinetics of crystallisation of ternary H2O-H2SO4-HNO3 mixtures to produce nitric acid hydrate phases, as occurs in the lower stratosphere, have been a long-standing challenge for investigators in the laboratory. Understanding polar stratospheric chlorine chemistry and thereby ozone depletion is increasingly limited by descriptions of nucleation processes. Meteoric smoke particles have been considered in the past as heterogeneous nuclei, however recent studies suggest that these particles will largely dissolve, leaving mainly silica and alumina as solid inclusions. In this study the nucleation kinetics of nitric acid hydrate phases have been measured in microliter droplets at polar stratospheric cloud (PSC) temperatures, using a droplet freezing assay. A clear heterogeneous effect was observed when silica particles were added. A parameterisation based on the number of droplets activated per nuclei surface area (ns) has been developed and compared to global model data. Nucleation experiments on identical droplets have been performed in an X-Ray Diffractometer (XRD) to determine the nature of the phase which formed. β-Nitric Acid Trihydrate (NAT) was observed alongside a mixture of Nitric Acid Dihydrate (NAD) phases. It is not possible to determine whether NAT nucleates directly or is formed by a phase transition from NAD (likely requiring the presence of a mediating liquid phase). Regardless, these results demonstrate the possibility of forming NAT on laboratory timescales. In the polar stratosphere, sulfuric acid (present at several weight percent of the liquid under equilibrium conditions) could provide such a liquid phase. This study therefor provides insight into previous discrepancies between phases formed in the laboratory and those observed in the atmosphere. It also provides a basis for future studies into atmospheric nucleation of solid PSCs.

  20. Extraction of actinides and nitric acid by crown ethers

    SciTech Connect

    Rozen, A.M.; Nikolotova, Z.I.; Kartasheva, N.A.; Luk'yanenko, N.G.; Bogatskii, A.V.

    1982-10-01

    This work studied the extraction of thorium nitrate, and an extraction isotherm of uranyl nitrate was obtained; the distribution of HNO/sub 3/ was studied over a wide range of acidity (up to 18M), which uses different concepts on the mechanism of the process. The extraction of Pu(VI) and Np(IV) was studied up to a 12 M acidity; two crown ethers had not previously been used for the extraction of the actinides. A quantitative description of the equilibria studied is given, and the influence of the structure of the ethers on the complex formation is discussed.

  1. Mechanistic studies of nitrations and oxidations in solutions of dinitrogen pentaoxide in nitric acid

    SciTech Connect

    Willmer, R.F.

    1992-01-01

    Mechanisms of nitrations in solutions of dinitrogen pentaoxide in nitric acid of 1,2,4-trichloro-5-nitrobenzene and 1,2-dichloro-4-nitrobenzene have been proposed. The kinetics and products of the nitration, in the title medium, of substantially deactivated benzoic acids and benzaldehydes have been investigated. Kinetics of nitration of some substituted benzoic acids in nitric acid solutions containing dinitrogen pentaoxide or nitronium trifluoro-methanesulphonate (nitronium triflate) have been compared. Rate coefficients for reactions in dinitrogen pentaoxide solutions were generally similar to those from nitronium triflate solutions of the same estimated nitronium ion concentration. Yields of aromatic products of nitration of some benzoic acid derivatives in the nitric acid solutions have been determined. Nitrodecarboxylation of 4-fluorobenzoic acid occurs as a result of nitronium ion attach at C(1). The competition between oxidation to the corresponding benzoic acid and nitration in the aromatic ring of some substituted benzaldehydes has been probed by kinetic and product studies. 4-Carboxybenzaldehyde is nitrated but more deactivated substrates are predominantly oxidized. Rapid reversible gem-dinitrate formation occurs in concentrated dinitrogen pentaoxide solutions. The equilibrium extent of formation of [alpha]-deuterio-(4-nitropheny)-dinitratomethane from [alpha]-deuterio-4-nitrobenzaldehyde is reported. 4-nitrobenzaldehyde and the gem-dinitrate are oxidized in processes in which [alpha]-hydrogen loss is at least partially rate determining. The relative rates of oxidation in nitronium triflate solutions suggest that the [alpha]-hydrogen is removed as a hydride ion in that medium. There is evidence for the intrusion of a radical mechanism of nitration in concentrated solutions of dinitrogen pentaoxide. (4-Nitrophenyl)dinitratomethane was produced on the addition of 4-nitrobenzaldehyde to a solution of dinitrogen pentaoxide in dichloromethane.

  2. Investigation on surface structure of potassium permanganate/nitric acid treated poly(tetrafluoroethylene)

    NASA Astrophysics Data System (ADS)

    Fu, Congli; Liu, Shuling; Gong, Tianlong; Gu, Aiqun; Yu, Zili

    2014-10-01

    In the previous articles concerning the treatment of poly(tetrafluoroethylene) (PTFE) with potassium permanganate/nitric acid mixture, the conversion of a hydrophobic to a hydrophilic surface was partially assigned to the defluorination of PTFE and then the introduction of carbonyl and hydroxyl groups into the defluorinated sites. In the present work, PTFE sheets were treated with potassium permanganate/nitric acid, and the surfaces before and after treatment were comparatively characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The surface sediments of the treated PTFE were also determined by atomic absorption spectroscopy (AAS). The results indicate that the conversion of the hydrophobicity to the hydrophilicity on the modified PTFE surface is mainly due to the deposition of hydrophilic manganese oxides which covered the fluorocarbon surface, and no detectable chemical reactions of PTFE occur in the treating process.

  3. Nitric acid and ammonia emissions from a mid-latitude prescribed wetlands fire

    NASA Astrophysics Data System (ADS)

    LeBel, P. J.; Cofer, W. R., III; Levine, J. S.; Vay, S. A.; Roberts, P. D.

    1988-08-01

    We have obtained the first simultaneous measurements of gaseous nitric acid (HNO3) and ammonia (NH3) in the smoke plume of a wetlands biomass burn. These measurements were made using tungsten oxide-coated diffusion denuder tubes from a helicopter during a prescribed burn at the Merritt Island National Wildlife Refuge, located at the NASA John F. Kennedy Space Center, Florida, on November 9, 1987. The mean NH3 and HNO3 mixing ratios measured in the smoke plume were 19 ppbv and 14 ppbv, respectively, both significantly higher than background mixing ratios. Nitric acid correlated well with carbon dioxide (CO2) produced by the combustion. The mean CO2-normalized emission ratio for HNO3 was found to be 1.2 × 10-4. Ammonia, however, did not correlate well with CO2 suggesting a more complex relationship between combustion and production/release of NH3.

  4. Nitric Oxide Regulates Mitochondrial Fatty Acid Metabolism through Reversible Protein S-Nitrosylation **

    PubMed Central

    Doulias, Paschalis-Thomas; Tenopoulou, Margarita; Greene, Jennifer L.; Raju, Karthik; Ischiropoulos, Harry

    2014-01-01

    Cysteine S-nitrosylation is a posttranslational modification by which nitric oxide regulates protein function and signaling. Studies of individual proteins have elucidated specific functional roles for S-nitrosylation, but knowledge of the extent of endogenous S-nitrosylation, the sites that are nitrosylated, and the regulatory consequences of S-nitrosylation remains limited. We used mass spectrometry-based methodologies to identify 1011 S-nitrosocysteine residues in 647 proteins in various mouse tissues. We uncovered selective S-nitrosylation of enzymes participating in glycolysis, gluconeogenesis, tricarboxylic acid cycle, and oxidative phosphorylation, indicating that this posttranslational modification may regulate metabolism and mitochondrial bioenergetics. S-nitrosylation of the liver enzyme VLCAD (very long acyl-CoA dehydrogenase) at Cys238, which was absent in mice lacking endothelial nitric oxide synthase, improved its catalytic efficiency. These data implicate protein S-nitrosylation in the regulation of β-oxidation of fatty acids in mitochondria. PMID:23281369

  5. Nitric acid and ammonia emissions from a mid-latitude prescribed wetlands fire

    NASA Technical Reports Server (NTRS)

    Lebel, P. J.; Cofer, W. R., III; Levine, J. S.; Vay, S. A.; Roberts, P. D.

    1988-01-01

    The first simultaneous measurements of gaseous nitric acid and ammonia in the smoke plume of a wetlands biomass burn were obtained. The measurements were made using tungsten oxide-coated diffusion denuder tubes from a helicopter during a prescribed burn on November 9, 1987, at the Merritt Island National Wildlife Refuge, located at the NASA John F. Kennedy Space Center, Florida. The mean NH3 and HNO3 mixing ratios measured in the smoke plume were 19 ppbv and 14 ppbv, respectively, both significantly higher than background mixing ratios. Nitric acid correlated well with carbon dioxide produced by the combustion. The mean CO2-normalized emission ratio for HNO3 was found to be 0.00012. Ammonia, however, dit not correlate well with CO2, suggesting a more complex relationship between combustion and production/release of NH3.

  6. Evaluation of the Magnesium Hydroxide Treatment Process for Stabilizing PFP Plutonium/Nitric Acid Solutions

    SciTech Connect

    Gerber, Mark A.; Schmidt, Andrew J.; Delegard, Calvin H.; Silvers, Kurt L.; Baker, Aaron B.; Gano, Susan R.; Thornton, Brenda M.

    2000-09-28

    This document summarizes an evaluation of the magnesium hydroxide [Mg(OH)2] process to be used at the Hanford Plutonium Finishing Plant (PFP) for stabilizing plutonium/nitric acid solutions to meet the goal of stabilizing the plutonium in an oxide form suitable for storage under DOE-STD-3013-99. During the treatment process, nitric acid solutions bearing plutonium nitrate are neutralized with Mg(OH)2 in an air sparge reactor. The resulting slurry, containing plutonium hydroxide, is filtered and calcined. The process evaluation included a literature review and extensive laboratory- and bench-scale testing. The testing was conducted using cerium as a surrogate for plutonium to identify and quantify the effects of key processing variables on processing time (primarily neutralization and filtration time) and calcined product properties.

  7. Comparison of parameterized nitric acid rainout rates using a coupled stochastic-photochemical tropospheric model

    NASA Technical Reports Server (NTRS)

    Stewart, Richard W.; Thompson, Anne M.; Owens, Melody A.; Herwehe, Jerold A.

    1989-01-01

    A major tropospheric loss of soluble species such as nitric acid results from scavenging by water droplets. Several theoretical formulations have been advanced which relate an effective time-independent loss rate for soluble species to statistical properties of precipitation such as the wet fraction and length of a precipitation cycle. In this paper, various 'effective' loss rates that have been proposed are compared with the results of detailed time-dependent model calculations carried out over a seasonal time scale. The model is a stochastic precipitation model coupled to a tropospheric photochemical model. The results of numerous time-dependent seasonal model runs are used to derive numerical values for the nitric acid residence time for several assumed sets of preciptation statistics. These values are then compared with the results obtained by utilizing theoretical 'effective' loss rates in time-independent models.

  8. Slice imaging of nitric acid photodissociation: The O({sup 1}D) + HONO channel

    SciTech Connect

    Herath, Nuradhika; Everhart, Stephanie C.; Suits, Arthur G.; Vasyuntinskii, Oleg S.

    2011-01-21

    We report an imaging study of nitric acid (HNO{sub 3}) photodissociation near 204 nm with detection of O({sup 1}D), one of the major decomposition products in this region. The images show structure reflecting the vibrational distribution of the HONO coproduct and significant angular anisotropy that varies with recoil speed. The images also show substantial alignment of the O({sup 1}D) orbital, which is analyzed using an approximate treatment that reveals that the polarization is dominated by incoherent, high order contributions. The results offer additional insight into the dynamics of the dissociation of nitric acid through the S{sub 3} (2 {sup 1}A{sup '}) excited state, resolving an inconsistency in previously reported angular distributions, and pointing the way to future studies of the angular momentum polarization.

  9. Photosynthetic and growth responses of Schima superba seedlings to sulfuric and nitric acid depositions.

    PubMed

    Yao, Fang-Fang; Ding, Hui-Ming; Feng, Li-Li; Chen, Jing-Jing; Yang, Song-Yu; Wang, Xi-Hua

    2016-05-01

    A continuing rise in acid deposition can cause forest degradation. In China, acid deposition has converted gradually from sulfuric acid deposition (SAD) to nitric acid deposition (NAD). However, the differing responses of photosynthesis and growth to depositions of sulfuric vs. nitric acid have not been well studied. In this study, 1-year-old seedlings of Schima superba, a dominant species in subtropical forests, were treated with two types of acid deposition SO4 (2-)/NO3 (-) ratios (8:1 and 0.7:1) with two applications (foliar spraying and soil drenching) at two pH levels (pH 3.5 and pH 2.5) over a period of 18 months. The results showed that the intensity, acid deposition type, and spraying method had significant effects on the physiological characteristics and growth performance of seedlings. Acid deposition at pH 2.5 via foliar application reduced photosynthesis and growth of S. superba, especially in the first year. Unlike SAD, NAD with high acidity potentially alleviated the negative effects of acidity on physiological properties and growth, probably due to a fertilization effect that improved foliar nitrogen and chlorophyll contents. Our results suggest that trees were damaged mainly by direct acid stress in the short term, whereas in the long term, soil acidification was also likely to be a major risk to forest ecosystems. Our data suggest that the shift in acid deposition type may complicate the ongoing challenge of anthropogenic acid deposition to ecosystem stability. PMID:26797956

  10. Multiple-acid equilibria in adsorption of carboxylic acids from dilute aqueous solution

    SciTech Connect

    Husson, S.M.; King, C.J.

    1999-02-01

    Equilibria were measured for adsorption of carboxylic acids from aqueous, binary-acid mixtures of lactic and succinic acids and acetic and formic acids onto basic polymeric sorbents. The experimentally determined adsorption isotherms compared well with model predictions, confirming that simple extensions from adsorption of individual acids apply. Fixed-bed studies were carried out that establish the efficacy of chromatographic fractionation of lactic and succinic acids using basic polymeric sorbents. Finally, sequential thermal and solvent regeneration of lactic and acetic acid-laden sorbents was investigated as a method to fractionate among coadsorbed volatile and nonvolatile acids. Essentially complete removal of the acetic acid from the acid-laden sorbent was achieved by vaporization under the conditions used; a small amount of loss of lactic acid (about 11%) was observed.

  11. Oleic acid-dependent modulation of Nitric oxide associated 1 protein levels regulates nitric oxide-mediated defense signaling in Arabidopsis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The conserved cellular metabolites nitric oxide (NO) and oleic acid (18:1) are well-known regulators of disease physiologies in diverse organism. We show that NO production in plants is regulated via 18:1. Reduction in 18:1 levels, via a genetic mutation in the 18:1-synthesizing gene SUPPRESSOR OF S...

  12. Search for an in-line nitric acid analyzer

    SciTech Connect

    Gallagher, K. Y.; Johnson, C. M.

    1980-10-01

    A literature search was conducted to identify possible techniques for measuring mineral acid normality in the presence of heavy metal salts, undissolved solids, and high radiation fields. Of the techniques noted, eight were identified that could be applicable to the objective. The possibilities were reduced to two methods, which warrant further investigation. These two are refractometry and a modified coulometric-polarographic method. All methods are discussed in detail followed by rationale for including or rejecting each for further investigation.

  13. Quantitative analysis of mixed hydrofluoric and nitric acids using Raman spectroscopy with partial least squares regression.

    PubMed

    Kang, Gumin; Lee, Kwangchil; Park, Haesung; Lee, Jinho; Jung, Youngjean; Kim, Kyoungsik; Son, Boongho; Park, Hyoungkuk

    2010-06-15

    Mixed hydrofluoric and nitric acids are widely used as a good etchant for the pickling process of stainless steels. The cost reduction and the procedure optimization in the manufacturing process can be facilitated by optically detecting the concentration of the mixed acids. In this work, we developed a novel method which allows us to obtain the concentrations of hydrofluoric acid (HF) and nitric acid (HNO(3)) mixture samples with high accuracy. The experiments were carried out for the mixed acids which consist of the HF (0.5-3wt%) and the HNO(3) (2-12wt%) at room temperature. Fourier Transform Raman spectroscopy has been utilized to measure the concentration of the mixed acids HF and HNO(3), because the mixture sample has several strong Raman bands caused by the vibrational mode of each acid in this spectrum. The calibration of spectral data has been performed using the partial least squares regression method which is ideal for local range data treatment. Several figures of merit (FOM) were calculated using the concept of net analyte signal (NAS) to evaluate performance of our methodology. PMID:20441916

  14. A Chamber Investigation of Nitric Acid-Soot Aerosol Chemistry at 298 K

    SciTech Connect

    Disselkamp, Robert S.; Carpenter, Michael A.; Cowin, James P.

    2000-10-02

    Long-pathlength infrared absorption spectroscopy was used to investigate nitric acid-soot aerosol chemistry at 298 K and 0.5 % relative humidity. Experiments were performed by introducing nitric acid vapor (PHNO3~3 Pa, Ptotal~40 kPa) into a teflon-coated chamber and initiating acquisition of infrared spectra at 3 minute time intervals. After 36 minutes of data collection, soot powder was rapidly expanded into nitric acid contained in the chamber to generate a soot-HNO3 aerosol. Infrared spectra collected before, and after, soot introduction to the chamber were used to characterize chamber wall reaction processes and soot aerosol chemistry, respectively. Three soot types were investigated (Degussa FW2, Cabot Monarch 1000, and crystalline graphite), each yielding similar chemistry. Upon soot introduction to the chamber both HNO3 uptake and NO2 production occurred, with the molar ratio of HNO3 uptake to NO2 production varying from 1.2 to 2.9 for the three soot types studied. Unreacted HNO3 was present at the conclusion of each of the aerosol experiments, indicating incomplete conversion of HNO3 into NO2. This observation suggested that "active" sites at the soot surface responsible for the reduction of HNO3 are not regenerated (i.e., formed) in the reaction process. In essence, a titration occurred between these active sites and HNO3. The NO2 concentrations produced, the soot mass concentrations used, and the BET measured specific surface area of the powders allowed computation of the surface density of active sites of ~4.0x10-18 m2/active site (describing all three powders studied). This is the first reported measurement of surface density of active sites for nitric acid chemistry on soot. Since atmospheric heterogeneous reactions that exhibit surface deactivation may, in principle, affect trace gas concentration, we perform an assessment in this regard.

  15. 77 FR 53144 - Nitric Acid; Exemption From the Requirement of a Tolerance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-31

    ...This regulation establishes an exemption from the requirement of a tolerance for residues of nitric acid (CAS Reg. No. 7697-37-2) when used as an inert ingredient in antimicrobial pesticide formulations applied to food-contact surfaces in public eating places, dairy processing equipment, and food-processing equipment and utensils at a maximum level in the end-use concentration of 1,000 parts......

  16. Autoclave leaching of molybdenite concentrates with catalytic additives of nitric acid

    NASA Astrophysics Data System (ADS)

    Smirnov, K. M.; Raspopov, N. A.; Shneerson, Ya. M.; Lapin, A. Yu.; Bitkov, G. A.; Men'shikov, Yu. A.; Paskhin, P. N.; Kirichenko, V. P.

    2010-07-01

    The scientific theoretical prerequisites for the use of small additives of nitric acid for the intensification of the autoclave oxidative leaching (AOL) of sulfide concentrates are checked in order to increase the degree of extraction of the base metal with a simultaneous decrease in the cost of the process. The technological parameters of the AOL conditions applied to molybdenite are also refined, and recommendations for a practical application of the apparatus of the process and for a decrease in its cost are made.

  17. The variation of nitric acid vapor and nitrate aerosol concentrations near the island of Hawaii

    SciTech Connect

    Lee, G.

    1992-01-01

    Anthropogenic emissions of nitrogen oxides (NO + NO[sub 2]) are estimated to be half of the global emissions to the atmosphere. To understand the effect of increasing anthropogenic reactive nitrogen inputs to the global atmosphere, one needs to monitor their long-term variations. This dissertation examines the variations of total nitrate (nitric acid vapor and nitrate aerosol) at the Mauna Loa Observatory (MLO), Hawaii. During the Mauna Loa Observatory Photochemistry Experiment (MLOPEX) in May, 1988, six different air types were identified at MLO with statistical analysis. They were: (1) volcano influenced air, (2) stratosphere-like air, (3) boundary-layer air with recent anthropogenic influence, (4) photochemical haze, (5) marine boundary-layer air, (6) well-aged and modified marine air. Samples that might be influenced by marine air or human activity from local islands were eliminated with three meterological criteria (wind direction, condensation nuclei, and dew point). To examine the negative sampling artifacts of nitric acid vapor due to ground loss, mixing ratio gradients with height were measured during August of 1991. The observed gradients of nitric acid vapor indicated that the long-term samplers at 8 m at MLO may underestimate the free tropospheric nitric acid vapor mixing ratio by about 20%. The three year mean and median of free tropospheric total nitrate during long-term measurements were 113 pptv and 93 pptv, respectively. Each year, the total nitrate mixing ratios at MLO during the spring and summer were increased by more than a factor of two higher than fall and winter. NO[sub y] from remote continents (Asia and North America) are likely sources of these increased total nitrate at MLO during these seasons. However, other processes govern the total nitrate mixing ratios, e.g., degree of mixing between free tropospheric air and boundary air at source regions, stratospheric injection, and wet removal of total nitrate.

  18. Methanol Uptake By Low Temperature Aqueous Sulfuric Acid Solutions

    NASA Technical Reports Server (NTRS)

    Iraci, Laura T.; Essin, Andrew M.; Golden, David M.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    To evaluate the role of upper tropospheric and lower stratospheric aerosols in the global budget of methanol, the solubility and reactivity of CH3OH in aqueous sulfuric acid solutions are under investigation. Using standard uptake techniques in a Knudsen cell reactor, we have measured the effective Henry's law coefficient, H(*), for methanol dissolution into 45 to 70 percent by weight H2SO4. We find that methanol solubility ranges from 10(exp 5) to 10(exp 8) M/atm and increases with decreasing temperature and with increasing sulfuric acid content. These solubility measurements include uptake due to physical solvation and all rapid equilibria which are established in solution. Our data indicate that simple uptake by aqueous sulfuric acid particles will not be a significant sink for methanol in the UT/LS. These results differ from those recently reported in the literature, and an explanation of this disparity will be presented. In addition to solvation, reaction between primary alcohols and sulfuric acid does occur, leading to the production of alkyl sulfates. Literature values for the rate of this reaction suggest that formation of CH3OSO3H may proceed in the atmosphere but is not significant under our experimental conditions. Results obtained using a complementary equilibrium measurement technique confirm this directly. In addition, the extent of methanol sequestration via formation of mono- and dimethylsulfate will be evaluated under several atmospheric conditions.

  19. Methanol Uptake by Low Temperature Aqueous Sulfuric Acid Solutions

    NASA Technical Reports Server (NTRS)

    Iraci, L. T.; Essin, A. M.; Golden, D. M.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    The global methanol budget is currently unbalanced, with source terms significantly larger than the sinks terms. To evaluate possible losses of gaseous methanol to sulfate aerosols, the solubility and reactivity of methanol in aqueous sulfuric acid solutions representative of upper tropospheric and lower stratospheric aerosols is under investigation. Methanol will partition into sulfate aerosols according to its Henry's law solubility. Using standard uptake techniques in a Knudsen cell reactor, we have measured the effective Henry's law coefficient, H*, for cold (196 - 220 K) solutions ranging between 45 and 70 wt % H2SO4. We have found that methanol solubility ranges from approx. 10(exp 5) - 10(exp 7) M/atm for UT/LS conditions. Solubility increases with decreasing temperature and with increasing sulfuric acid content. Although methanol is slightly more soluble than are acetone and formaldehyde, current data indicate that uptake by clean aqueous sulfuric acid particles will not be a significant sink for methanol in the UT/LS. These solubility measurements include uptake due to physical solvation and any rapid equilibria which are established in solution. Reaction between primary alcohols and sulfuric acid does occur, leading to the production of alkyl sulfates. Literature values for the rate of this reaction suggest that formation of CH3OSO3H is not significant over our experimental time scale for solutions below 80 wt % H2SO4. To confirm this directly, results obtained using a complementary equilibrium measurement technique will also be presented.

  20. Initiation Temperature for Runaway Tri-n-Butyl Phosphate/Nitric Acid Reaction

    SciTech Connect

    Rudisill, T.S.

    2000-11-28

    During a review of the H-Canyon authorization basis, Defense Nuclear Facility Safety Board (DNFSB) staff members questioned the margin of safety associated with a postulated tri-n-butyl phosphate (TBP)/nitric acid runaway reaction due to the inadvertent heating of a canyon tank containing greater than 3000 lbs (1362 kg) of TBP. The margin of safety was partially based on experiments and calculations performed by the Actinide Technology Section (ATS) to support deletion of indication of tank agitation as a Safety Class System. In the technical basis for deletion of this system, ATS personnel conservatively calculated the equilibrium temperature distribution of a canyon tank containing TBP and nitric acid layers which were inadvertently heated by a steam jet left on following a transfer. The maximum calculated temperature (128 degrees C) was compared to the minimum initiation temperature for a runaway reaction (greater than 130 degrees C) documented by experimental work in the mid 195 0s. In this work, the initiation temperature as a function of nitric acid concentration was measured for 0 and 20 wt percent dissolved solids. The DNFSB staff members were concerned that data for 0 wt percent dissolved solids were not conservative given the facts that data for 20 wt percent dissolved solids show initiation temperatures at or below 130 degrees C and H-Canyon solutions normally contained a small amount of dissolved solids.

  1. Measurements of tropospheric nitric acid over the Western United States and Northeastern Pacific Ocean

    SciTech Connect

    Lebel, P.J.; Huebert, B.J.; Schiff, H.I.; Vay, S.A.; Vanbramer, S.E.; Hastie, D.R.

    1990-01-01

    Over 240 measurements of nitric acid (HNO{sub 3}) were made in the free troposphere as well as in the boundary layer. Marine HNO{sub 3} measurement results were strikingly similar to results from GAMETAG and other past atmospheric field experiments. The marine boundary layer HNO{sub 3} average, 62 parts-per-trillion by volume (pptv), was 1/3 lower than the marine free tropospheric average, 108 pptv, suggesting that the boundary layer is a sink for tropospheric nitric acid, probably by dry deposition. Nitric acid measurements on a nighttime continental flight gave a free tropospheric average of 218 pptv, substantially greater than the daytime continental free tropospheric 5-flight average of 61 pptv. However, the nighttime results may be influenced by highly convective conditions that existed from thunderstorms in the vicinity during that night flight. The continental boundary layer HNO{sub 3} average of 767 pptv is an order of magnitude greater than the free tropospheric average, indicating that the boundary layer is a source of free tropospheric HNO{sub 3}. The distribution of continental boundary layer HNO{sub 3} data, from averages of 123 over rural Nevada and Utah to 1057 pptv in the polluted San Joaquin Valley of California suggest a close tie between boundary layer HNO{sub 3} and anthropogenic activity.

  2. Measurements of tropospheric nitric acid over the Western United States and Northeastern Pacific Ocean

    NASA Technical Reports Server (NTRS)

    Lebel, P. J.; Huebert, B. J.; Schiff, H. I.; Vay, S. A.; Vanbramer, S. E.; Hastie, D. R.

    1990-01-01

    Over 240 measurements of nitric acid (HNO3) were made in the free troposphere as well as in the boundary layer. Marine HNO3 measurement results were strikingly similar to results from GAMETAG and other past atmospheric field experiments. The marine boundary layer HNO3 average, 62 parts-per-trillion by volume (pptv), was 1/3 lower than the marine free tropospheric average, 108 pptv, suggesting that the boundary layer is a sink for tropospheric nitric acid, probably by dry deposition. Nitric acid measurements on a nighttime continental flight gave a free tropospheric average of 218 pptv, substantially greater than the daytime continental free tropospheric 5-flight average of 61 pptv. However, the nighttime results may be influenced by highly convective conditions that existed from thunderstorms in the vicinity during that night flight. The continental boundary layer HNO3 average of 767 pptv is an order of magnitude greater than the free tropospheric average, indicating that the boundary layer is a source of free tropospheric HNO3. The distribution of continental boundary layer HNO3 data, from averages of 123 over rural Nevada and Utah to 1057 pptv in the polluted San Joaquin Valley of California suggest a close tie between boundary layer HNO3 and anthropogenic activity.

  3. Measurements of tropospheric nitric acid over the western United States and northeastern Pacific Ocean

    SciTech Connect

    LeBel, P.J.; Vay, S.A. ); Huebert, B.J. ); Schiff, H.I.; Hastie, D.R. ); Van Bramer, S.E. )

    1990-06-20

    During the August-September 1986 GTE/CITE 2 aircraft mission, more than 240 measurements of nitric acid (HNO{sub 3}) were made in the free troposphere as well as in the boundary layer over the northeastern Pacific Ocean and western continental United States. Marine HNO{sub 3} measurement results were strikingly similar to results from GAMETAG and other past atmospheric field experiments. The marine boundary layer HNO{sub 3} average, 62 parts per trillion by volume (pptv), was one third lower than the marine free tropospheric average, 108 pptv, suggesting that the boundary layer is a sink for tropospheric nitric acid, probably by dry deposition. Nitric acid measurements on a nighttime continental flight gave a free tropospheric average of 218 pptv, substantially greater than the daytime continental free tropospheric five-flight average of 61 pptv. However, the nighttime results may have been influenced by highly convective conditions that existed from thunderstorms in the vicinity during that night flight. Our continental boundary layer HNO{sub 3} average of 767 pptv is an order of magnitude greater than the free tropospheric average, indicating that the boundary layer is a source of free tropospheric HNO{sub 3}. The distribution of continental boundary layer HNO{sub 3} data, from averages of 123 pptv over rural Nevada and Utah to 1,057 pptv in the polluted San Joaquin Valley of California suggests a close tie between boundary layer HNO{sub 3} and anthropogenic activity.

  4. Ignition Delays of Alkyl Thiophosphites with White and Red Fuming Nitric Acids Within Temperature Range 80 to -105 F

    NASA Technical Reports Server (NTRS)

    Miller, Riley O; Ladanyi, Dezso J

    1953-01-01

    Ignition delays of alkyl thiophosphites were obtained in a modified open-cup apparatus and a small-scale rocket engine apparatus. At -40 F, mixed alkyl thiophosphites gave short delays with white fuming nitric acid containing 2 percent water and red fuming nitric acids of widely varying compositions. At -40 F and higher, triethyl trithiophosphite blended with as much as 40 percent n-heptane gave satisfactory self-igniting properties at temperatures as low as -76 F.

  5. Novel amino acids: synthesis of furoxan and sydnonimine containing amino acids and peptides as potential nitric oxide releasing motifs.

    PubMed

    Nortcliffe, Andrew; Botting, Nigel P; O'Hagan, David

    2013-07-28

    The incorporation of furoxan and sydnonimine ring systems into amino acid side chains is demonstrated with the preparation of four novel amino acids which carry these nitric oxide-releasing motifs. N-((4-Nitrophenoxy)carbonyl)-3-phenylsydnonimine 9 and bis(phenylsulfonyl)furoxan 10 are the key intermediates for introducing the heterocycle side chains onto appropriate amine and alcohol functionalities respectively. Furoxan 5 and 7 both displayed NO release based on determination of nitrite production. Orthogonal amino acid protecting group strategies were deployed to demonstrate that the amino acids could be incorporated into peptide frameworks. By way of demonstration the amino acids were placed centrally into several tripeptide motifs. Griess test assays showed that these amino acids released NO in the presence of γ-glutathione (GST). PMID:23753002

  6. Sulfuric, hydrochloric, and nitric acid-catalyzed triacetone triperoxide (TATP) reaction mixtures: an aging study.

    PubMed

    Fitzgerald, Mark; Bilusich, Daniel

    2011-09-01

    The organic peroxide explosive triacetone triperoxide (TATP) is regularly encountered by law enforcement agents in various stages of its production. This study utilizes solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) to examine sulfuric acid-, hydrochloric acid-, and nitric acid-catalyzed TATP syntheses during the initial 24 h of these reactions at low temperatures (5-9°C). Additionally, aging of the reaction mixtures was examined at both low and ambient temperatures (19-21°C) for a further 9 days. For each experiment, TATP could be readily identified in the headspace above the reaction mixture 1 h subsequent to the combination of reagents; at 24 h, TATP and diacetone diperoxide (DADP) were prominent. TATP degraded more rapidly than DADP. Additionally, chlorinated acetones chloroacetone and 1,1,-dichloroacetone were identified in the headspace above the hydrochloric acid-catalyzed TATP reaction mixture. These were not present when the catalyst was sulfuric acid or nitric acid. PMID:21595692

  7. Evaluation of oxygen pressurized microwave-assisted digestion of botanical materials using diluted nitric acid.

    PubMed

    Bizzi, Cezar Augusto; Barin, Juliano Smanioto; Müller, Edson Irineu; Schmidt, Lucas; Nóbrega, Joaquim A; Flores, Erico Marlon Moraes

    2011-02-15

    The feasibility of diluted nitric acid solutions for microwave-assisted decomposition of botanical samples in closed vessels was evaluated. Oxygen pressurized atmosphere was used to improve the digestion efficiency and Al, Ca, K, Fe, Mg and Na were determined in digests by inductively coupled plasma optical emission spectrometry (ICP OES). Efficiency of digestion was evaluated taking into account the residual carbon content (RCC) and residual acidity in digests. Samples were digested using nitric acid solutions (2, 3, 7, and 14 mol L(-1) HNO(3)) and the effect of gas phase composition inside the reaction vessels by purging the vessel with Ar (inert atmosphere, 1 bar), air (20% of oxygen, 1 bar) and pure O(2) (100% of oxygen, 1 bar) was evaluated. The influence of oxygen pressure was studied using pressures of 5, 10, 15 and 20 bar. It was demonstrated that a diluted nitric acid solution as low as 3 mol L(-1) was suitable for an efficient digestion of sample masses up to 500 mg of botanical samples using 5 bar of oxygen pressure. The residual acidities in final digests were lower than 45% in relation to the initial amount of acid used for digestion (equivalent to 1.3 mol L(-1) HNO(3)). The accuracy of the proposed procedure was evaluated using certified reference materials of olive leaves, apple leaves, peach leaves and pine needles. Using the optimized conditions for sample digestion, the results obtained were in agreement with certified values. The limit of quantification was improved up to a factor of 14.5 times for the analytes evaluated. In addition, the proposed procedure was in agreement with the recommendations of the green chemistry once it was possible to obtain relatively high digestion efficiency (RCC<5%) using only diluted HNO(3), which is important to minimize the generation of laboratory residues. PMID:21238716

  8. Dephosphorization of Steelmaking Slag by Leaching with Acidic Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Qiao, Yong; Diao, Jiang; Liu, Xuan; Li, Xiaosa; Zhang, Tao; Xie, Bing

    2015-12-01

    In the present paper, dephosphorization of steelmaking slag by leaching with acidic aqueous solution composed of citric acid, sodium hydroxide, hydrochloric acid and ion-exchanged water was investigated. The buffer solution of C6H8O7-NaOH-HCl system prevented changes in the pH values. Kinetic parameters including leaching temperature, slag particle size and pH values of the solution were optimized. The results showed that temperature has no obvious effect on the dissolution ratio of phosphorus. However, it has a significant effect on the dissolution ratio of iron. The dephosphorization rate increases with the decrease of slag particle size and the pH value of the solution. Over 90% of the phosphorus can be dissolved in the solution while the corresponding leaching ratio of iron was only 30% below the optimal condition. Leaching kinetics of dephosphorization follow the unreacted shrinking core model with a rate controlled step by the solid diffusion layer, the corresponding apparent activation energy being 1.233 kJ mol-1. A semiempirical kinetic equation was established. After leaching, most of the nC2S-C3P solid solution in the steelmaking slag was selectively dissolved in the aqueous solution and the iron content in the solid residue was correspondingly enriched.

  9. Hydrogen generation during IDMS demonstrations of the Late Washing and Nitric Acid flowsheets

    SciTech Connect

    Ritter, J.A.

    1992-10-19

    Recently, Late Washing (LW) and Nitric Acid (NA) flowsheets, developed respectively for the DWPF at Savannah River Technology Center SPC and CPC, were demonstrated in the one-fifth scale DWPF pilot facilities, PHEF and IDMS. Using the LW flowsheet, four runs in the PHEF produced enough PHA for two runs in the IDMS (denoted by PX4 and PX5). One of the objectives of these IDMS runs was to obtain peak hydrogen generation rates and compare them to the peak hydrogen generation rate design basis obtained from a previous IDMS run, based on the HAN and Formic Acid (HAN-FA) flowsheets.

  10. Fermentation of aqueous plant seed extracts by lactic acid bacteria

    SciTech Connect

    Schafner, D.W.; Beuchat, R.L.

    1986-05-01

    The effects of lactic acid bacterial fermentation on chemical and physical changes in aqueous extracts of cowpea (Vigna unguiculata), peanut (Arachis hypogea), soybean (Glycine max), and sorghum (Sorghum vulgare) were studied. The bacteria investigated were Lactobacillus helveticus, L. delbrueckii, L. casei, L. bulgaricus, L. acidophilus, and Streptococcus thermophilus. Organisms were inoculated individually into all of the seed extracts; L. bulgaricus and S. thermophilus were also evaluated together as inocula for fermenting the legume extracts. During fermentation, bacterial population and changes in titratable acidity, pH, viscosity, and color were measured over a 72 h period at 37 degrees C. Maximum bacterial populations, titratable acidity, pH, and viscosity varied depending upon the type of extract and bacterial strain. The maximum population of each organism was influenced by fermentable carbohydrates, which, in turn, influenced acid production and change in pH. Change in viscosity was correlated with the amount of protein and titratable acidity of products. Color was affected by pasteurization treatment and fermentation as well as the source of extract. In the extracts inoculated simultaneously with L. bulgaricus and S. thermophilus, a synergistic effect resulted in increased bacterial populations, titratable acidity, and viscosity, and decreased pH in all the legume extracts when compared to the extracts fermented with either of these organisms individually. Fermented extracts offer potential as substitutes for cultured dairy products. 24 references.